The Periodic Table EXPLAINED | Chemical Families and Periodic Trends

Summary

This video script offers an insightful look into the periodic table's history and organization. It highlights the contributions of Dmitri Mendeleev and Henry Moseley, leading to the current structure based on atomic number. The script explains the periodic law, grouping of elements into families like alkali metals, alkaline earth metals, transition metals, halogens, and noble gases, and discusses key trends such as atomic radius, ionization energy, and electronegativity. It also covers how these trends predict element properties, making the periodic table an essential tool in chemistry.

Takeaways

• 🌐 The periodic table is an iconic symbol in chemistry, recognized worldwide.
• 📚 There have been many ways to organize elements, but the current periodic table is the most widely accepted.
• 🔬 Dmitri Mendeleev's periodic table organized elements by increasing atomic mass and predicted properties of undiscovered elements.
• 🔍 Henry Moseley's research led to the discovery of the atomic number, which rearranged the periodic table.
• 📊 The modern periodic table is organized by increasing atomic number, leading to the periodic law.
• 🔑 The periodic law states that elements with similar properties are grouped together when organized by atomic number.
• 📈 The table is divided into rows (periods) and columns (groups or families), with three broad categories: metals, non-metals, and metalloids.
• 🔬 Metalloids like silicon have properties of both metals and non-metals and are known as semiconductors.
• 📚 Specific groups on the periodic table include alkali metals, alkaline earth metals, transition metals, halogens, and noble gases.
• 📉 Trends in the periodic table include atomic radius, ionization energy, and electronegativity, which can predict element properties.
• 🔋 Ionization energy increases from left to right across a period and decreases as you move down a column.
• 🔑 Electronegativity increases from left to right across a period and decreases as you move down a column, with noble gases having zero electronegativity.

Q & A

Who is credited with designing the first widely accepted periodic table?

The first widely accepted periodic table was designed by a Russian scientist named Dmitri Mendeleev.

How did Dmitri Mendeleev organize the elements in his periodic table?

Dmitri Mendeleev organized the elements by increasing atomic mass, which allowed him to predict the properties of other elements and even predict the existence of undiscovered elements.

What significant discovery by Henry Moseley led to the modern periodic table?

Henry Moseley's research involving X-rays of elements led to the discovery of the atomic number, which is the exact number of protons in the nucleus of an atom. This discovery prompted the rearrangement of the periodic table to organize elements by increasing atomic number.

What is the periodic law and how does it relate to the organization of the periodic table?

The periodic law states that when elements are organized by increasing atomic number, they will be grouped by common properties. The properties of elements can be predicted by trends and patterns.

What are the three broad categories of elements in the periodic table?

The three broad categories of elements in the periodic table are metals, non-metals, and metalloids.

How does the property of elements change as you move from left to right across the periodic table?

As you move from left to right across the periodic table, elements become less metallic. This is due to the increase in the positive charge of the nucleus, which pulls the electron energy levels closer, making atoms smaller and less metallic.

What are metalloids and where are they located on the periodic table?

Metalloids are elements that have properties of both metals and non-metals. They are located near the stair-step line that separates metals from non-metals on the periodic table.

What are the common families or groups of elements found in the same column of the periodic table?

Common families or groups of elements found in the same column of the periodic table include alkali metals, alkaline earth metals, transition metals, halogens, and noble gases.

How does atomic radius change as you move down a column in the periodic table?

As you move down a column in the periodic table, atoms get larger because each time you move down a row, you add another energy level.

What is ionization energy and how does it change across the periodic table?

Ionization energy is the energy required to remove an electron from the valence shell. It increases from left to right across a period and decreases as you move down a column.

How does electronegativity change as you move across and down the periodic table?

Electronegativity increases from left to right across the periodic table and decreases as you move down a column. This is because atoms want to achieve a stable electron configuration, typically with eight electrons in their outermost shell.

Which element has the highest electronegativity and why?

Fluorine has the highest electronegativity because it is the farthest to the right and top of the periodic table, indicating a strong ability to attract electrons.

Outlines

00:00

🔬 Introduction to the Periodic Table and its Evolution

This paragraph introduces the periodic table as an iconic symbol in chemistry, appearing in classrooms and on merchandise. It highlights that various attempts have been made to organize elements in different ways, many of which seemed chaotic. Eventually, the modern version was developed. The lesson plan includes learning about the history of the periodic table, chemical families, and how the table predicts element properties based on patterns and trends.

05:01

📜 History of the Periodic Table

Dmitri Mendeleev, a Russian scientist, created the first widely accepted periodic table by organizing elements by increasing atomic mass. His system was groundbreaking because it allowed him to predict the properties and existence of undiscovered elements, as shown by blanks in his table. In 1913, British scientist Henry Moseley discovered the atomic number, leading to the modern arrangement of the periodic table by atomic number. This reorganization established the periodic law, which states that elements organized by atomic number display common properties and predictable patterns.

📏 Structure of the Modern Periodic Table

The modern periodic table consists of neatly arranged rows (periods) and columns (groups or families). Elements are grouped into three broad categories: metals, non-metals, and metalloids. Metals are typically hard, shiny, and conduct electricity, while non-metals, mostly gases, are brittle and poor conductors. The elements bordering the 'stair-step' line on the table are metalloids, exhibiting properties of both metals and non-metals. As one moves across the table from left to right, elements tend to become less metallic.

🔎 Chemical Families in the Periodic Table

The periodic table contains specific families of elements with shared properties. The alkali metals (first column) are soft and reactive, becoming more reactive down the group. Alkaline earth metals (second column) are harder and less reactive. Transition metals occupy the middle of the table and are generally less reactive, with mercury being a liquid. Halogens are reactive non-metals, becoming less reactive as you move down the group. Finally, the noble gases are inert gases that do not react easily. Each group exhibits distinct characteristics based on its position.

📏 Periodic Trends: Atomic Radius

Atomic radius, or the size of an atom, is defined as the distance between two bonding nuclei. As one moves down a column in the periodic table, atoms increase in size due to additional energy levels. However, as one moves from left to right across a period, atoms become smaller due to the increasing positive charge in the nucleus, which pulls the energy levels closer together. This trend explains why a neon atom is smaller than a carbon atom despite being in the same period.

⚡ Periodic Trends: Ionization Energy

Ionization energy refers to the energy required to remove an electron from an atom. Atoms generally prefer to have eight electrons in their outermost shell (valence shell). Metals, which tend to lose electrons, have low ionization energy, while non-metals, which prefer to gain electrons, have high ionization energy. As you move from left to right across a period, ionization energy increases, while moving down a column decreases ionization energy due to the increased distance between valence electrons and the nucleus.

🧲 Periodic Trends: Electronegativity

Electronegativity is the ability of an atom to attract electrons. Metals generally have low electronegativity, while non-metals have high electronegativity. As one moves from left to right across a period, electronegativity increases, while moving down a column, it decreases. Although noble gases have full valence shells and should theoretically have high electronegativity, they do not participate in gaining or losing electrons, giving them an electronegativity of zero. Fluorine, at the top right of the periodic table, has the highest electronegativity.

🎯 Key Takeaways from the Periodic Table

This concluding section reinforces the main points of the lesson. The modern periodic table is organized by increasing atomic number. It categorizes elements into three broad types—metals, non-metals, and metalloids—with elements in the same column having similar properties, referred to as chemical families. Additionally, the periodic table is useful for predicting trends, such as atomic radius, ionization energy, and electronegativity, which help to understand the behavior and characteristics of elements.

Keywords

💡Periodic Table

The Periodic Table is a tabular arrangement of chemical elements organized on the basis of their atomic number, electron configurations, and recurring chemical properties. It is a fundamental tool in chemistry, education, and research. In the video, the Periodic Table is described as an iconic symbol of chemistry that has been adapted into various cultural artifacts and is essential for predicting the properties of elements.

💡Dmitri Mendeleev

Dmitri Mendeleev was a Russian scientist who is credited with creating the first widely accepted periodic table. He organized the elements by increasing atomic mass, which allowed him to predict the properties of other elements and even the existence of undiscovered elements. Mendeleev's work is foundational to the video's discussion of the periodic table's history and its predictive capabilities.

💡Atomic Number

The atomic number is the number of protons found in the nucleus of an atom. It is a key identifier of an element. In the video, the discovery of the atomic number by Henry Moseley led to a significant reorganization of the periodic table, resulting in the modern version that arranges elements by increasing atomic number.

💡Periodic Law

The Periodic Law states that the properties of elements are a periodic function of their atomic number. This law is a natural outcome of the periodic table's organization and is central to the video's explanation of how elements with common properties are grouped together.

💡Groups/Chemical Families

Groups or chemical families refer to the columns of the periodic table. Elements within the same group tend to have similar chemical properties. The video explains that there are broad categories and more specific families, such as alkali metals, alkaline earth metals, transition metals, halogens, and noble gases.

💡Metals

Metals are a broad category of elements found on the left side of the periodic table's 'stair step'. They are typically hard, shiny, conductive, malleable, and ductile. The video uses metals to illustrate how elements become less metallic as you move from left to right across the table.

💡Non-Metals

Non-metals are elements found to the right of the 'stair step' on the periodic table. They are often gases but can also be solids or liquids. Non-metals do not conduct electricity and are brittle when solid. The video contrasts non-metals with metals to show how their properties are generally opposite.

💡Metalloids

Metalloids are elements that have properties of both metals and non-metals. They are located near the 'stair step' border between metals and non-metals on the periodic table. An example given in the video is silicon, which is shiny and solid but also brittle and a poor conductor of electricity, making it a semiconductor.

💡Atomic Radius

Atomic radius is the size of an atom, typically measured as the distance between the nuclei of two bonded atoms. The video explains that atoms generally get larger as you move down a column in the periodic table due to the addition of energy levels, and smaller as you move from left to right due to increasing nuclear charge pulling electron shells closer.

💡Ionization Energy

Ionization energy is the energy required to remove an electron from an atom's valence shell. The video describes how ionization energy increases from left to right across a period in the periodic table, making it harder to remove electrons, and decreases down a group as electrons are further from the nucleus.

💡Electronegativity

Electronegativity is the ability of an atom to attract electrons towards itself. The video explains that electronegativity generally increases across a period from left to right and decreases down a group. It is used to predict how likely an atom is to gain or lose electrons, with non-metals typically having higher electronegativity than metals.

Highlights

The periodic table is an iconic symbol of chemistry, appearing on various merchandise and in science classrooms worldwide.

There have been many different ways to organize the elements, some looking quite unusual.

The modern periodic table was developed to help predict the properties of elements and even the existence of undiscovered elements.

Dmitri Mendeleev designed the first widely accepted periodic table, organizing elements by increasing atomic mass.

Henry Moseley's research with X-rays led to the discovery of the atomic number, which revolutionized the periodic table's organization.

The modern periodic table is organized by increasing atomic number, leading to the creation of the periodic law.

Elements are grouped into families with common properties, with three broad categories: metals, non-metals, and metalloids.

Metals are typically found on the left side of the periodic table and share similar properties.

Non-metals are generally found on the right side and have properties opposite to metals.

Metalloids, like silicon, have properties of both metals and non-metals and are located near the stair-step line of the table.

The periodic table is divided into periods (rows) and groups (columns), with each group sharing similar chemical properties.

Alkali metals are soft and reactive, becoming more so as you move down the column.

Alkaline earth metals are less reactive and harder than alkali metals.

Transition metals are generally less reactive and are mostly solid metals, except for mercury.

Halogens are very reactive non-metals, becoming less reactive as you move down the column.

Noble gases are unreactive gases with complete valence shells, making them inert.

The periodic table allows for the prediction of element properties based on trends in atomic radius, ionization energy, and electronegativity.

Atomic radius generally increases as you move down a column and decreases across a period from left to right.

Ionization energy is the energy required to remove an electron, with metals having lower ionization energies than non-metals.

Electronegativity is the ability of an atom to attract electrons, with non-metals generally having higher electronegativity than metals.

Fluorine has the highest electronegativity of all elements.

Transcripts

it's probably one of the most iconic

symbols of chemistry it has made its way

onto t-shirts and coffee mugs and of

course science classrooms all over the

world which you may not have been aware

of is that there's been many different

ways to organize the elements and some

of them have looked pretty crazy but

eventually we landed on this one this

lesson is all about the periodic

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table so what are we going to learn in

this lesson first we'll learn the

history of the modern periodic table and

then we'll learn the properties of some

of the chemical families on the periodic

table and then finally we'll learn how

the periodic table can be used to

predict the properties of elements

according to patterns and Trends the

first widely accepted periodic table was

designed by a Russian scientist named

Demitri menl he organized The Elements

by increasing atomic mass his periodic

table was useful because it organized

elements in such a way he could predict

the properties of other elements and

even predict the existence of

undiscovered elements you can notice the

blanks and question marks in his

periodic table in 1913 a British

scientist named Henry Mosley made a

breakthrough with his research involving

X-rays of elements that led to the

discovery of the atomic number the

atomic number is the exact number of

protons in the nucleus of the atom the

periodic table is rearranged to organize

Elements by increasing atomic number and

the modern periodic table was created

the natural outcome of this organization

was the periodic law which states that

when elements are organized by

increasing atomic number the elements

will be grouped by Common properties and

the properties of elements can be

predicted by Trends and patterns the

modern periodic table has nice neat rows

and columns The Columns are called

groups or chemical families and the rows

are called periods the modern per table

has been arranged so that elements are

grouped into families there are three

broad families or categories of elements

and then there are five more specific

families that we're going to learn the

three broad categories are metals

non-metals and metalloids metals are

elements on the left side of the stair

step Metals share similar properties

with one another in general they are

hard shiny they conduct electricity they

are malleable and ductile non-metals are

to the right of the stair step in

general their properties are the

opposite of metals they're mostly gases

but they can be solid or liquid they

don't conduct electricity and they are

brittle when they are solid the stair

step isn't a definite border between

metals and non-metals in general As you

move from the left to right across the

periodic table elements are going to

become less metallic some of the

elements that touch the stair step have

equal properties of both metals and

non-metals we call these elements

metalloids like Silicon silicon is shiny

and solid yet it's very brittle it

conducts electricity but only slightly

we call it a semiconductor there are

some more specific groups on the

periodic table in general elements that

are in the same column will share

similar properties here are some of the

common families

First Column is the alkaline metals

second column is the alkaline earth

metals this middle section is called the

transition metals this column over here

is called the halogens and then this

last column is the noble gases alkali

metals are soft reactive metals they

become more reactive and softer As you

move down the column alkaline earth

metals are hard reactive metals a little

less reactive than the alkali metals the

transition metals are generally not as

reactive as Alkali or alkaline earth

metals they are solid Metals except for

mercury which is a liquid at room

temperature Hallens are very reactive

non-metals they are gases at the top of

the family and they become solid as you

move down the column they are the most

reactive elements on the periodic table

they are most reactive at the top and

they get less reactive As you move down

the column opposite the trend of alkali

metals finally the noble gases are all

gases they are unreactive or in other

words inert the periodic table is useful

for predic the properties of elements

according to patterns and Trends we call

this periodic law or periodicity we will

talk about three Trends atomic radius

ionization energy and electr negativity

first atomic radius this is the size of

an atom it's defined as the distance

between two bonding nuclei it's a weird

sounding definition but remember that

electrons are in funny shaped clouds

they don't really have a definite Edge

the nucleus on the other hand is dense

and unmoving part of the atom so when

two atoms bond we can measure the

distance between the two

nuclei in general atoms get larger As

you move down a column this is because

each time you move down a row you add

another energy level I'll show you by

comparing lithium to sodium notice that

sodium has an additional energy level as

compared to lithium in general atoms get

smaller as you move from left to right

across the period take period number two

each element has the same number of

occupied energy levels but the charge in

the nucleus increases because one proton

is added as we move from element to

element across a periodic table the

greater the charge of the nucleus the

greater the pull on those energy levels

and they get pulled in closer and closer

so a neon atom is smaller than a carbon

atom next is ionization energy atoms can

lose or gain electrons why would they

want to do that well in general atoms

want to have eight electrons in their

outermost energy level this energy level

is called the veence energy level or

veence shell there are two ways to get

eight electrons elements could lose

their veence electrons and uncover a new

veence shell or gain electrons to

complete their current veence Shell

let's compare chlorine to sodium sodium

will lose one electron to uncover a

stable valence shell beneath chlorine

will gain one veence electron to

complete its current veent shell atoms

that have lost electrons are called cat

ions and when an atom turns into a A

cation it gets smaller atoms that have

gained electrons are called anion and

when an atom turns into an anion it gets

larger ionization energy is the energy

required to remove an electron from the

veent shell the greater the ionization

energy the more difficult it is to

remove an electron metals have low

ionization energies it's easier to

remove electrons from a metal than it is

from a non-metal non-metals have high

ionization energies it's more difficult

to remove an electron from a nonmetal

because they would rather gain electrons

just like chlorine As you move from left

to right across a period the ionization

energy will increase as you move down a

column the ionization energy will

decrease the reason ionization energy

decreases as you move down is because as

you move down a column you add a new

energy level each time and so the veence

electrons are further and further away

from the nucleus they're further away

from the positive charge that's pulling

on the electrons and so it's easier to

remove an electron and so Florine has a

higher ionization energy than Boron

electro negativity is kind of the

opposite of ionization energy electr

negativity is the ability of an atom to

attract electrons to itself in General

Metals have low electro negativity and

non-metals have high electr negativity a

high electr negativity means that the

atom has a strong ability to attract

electrons to itself so moving from left

to right across the periodic table the

electro negativity increases moving down

a column the electro negativity

decreases according to this trend noble

gases should have the highest electr

negativity or the greatest pull in

electrons but remember that noble gases

have eight veence electrons and so they

don't want to gain or lose electrons so

the electr negativity of noble gases

would be nothing it'd be zero so which

element has the highest

electronegativity well that would be

Florine because Florine is the furthest

to the right and furthest to the top so

did you learn everything in this lesson

well if you did you learn that the

modern period table is organized by

increasing atomic number there are three

broad categories of elements metals

non-metals and metalloids elements in

the same column are similar to one

another we call these chemical families

or groups finally we learned about three

different Trends in the periodic table

electro negativity ionization energy and

atomic radius

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