The Periodic Table EXPLAINED | Chemical Families and Periodic Trends
Summary
TLDRThis 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
- đ The periodic table is an iconic symbol in chemistry, recognized worldwide.
- đ There have been many ways to organize elements, but the current periodic table is the most widely accepted.
- đŹ Dmitri Mendeleev's periodic table organized elements by increasing atomic mass and predicted properties of undiscovered elements.
- đ Henry Moseley's research led to the discovery of the atomic number, which rearranged the periodic table.
- đ The modern periodic table is organized by increasing atomic number, leading to the periodic law.
- đ The periodic law states that elements with similar properties are grouped together when organized by atomic number.
- đ The table is divided into rows (periods) and columns (groups or families), with three broad categories: metals, non-metals, and metalloids.
- đŹ Metalloids like silicon have properties of both metals and non-metals and are known as semiconductors.
- đ Specific groups on the periodic table include alkali metals, alkaline earth metals, transition metals, halogens, and noble gases.
- đ Trends in the periodic table include atomic radius, ionization energy, and electronegativity, which can predict element properties.
- đ Ionization energy increases from left to right across a period and decreases as you move down a column.
- đ 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
đŹ 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.
đ 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.
đ 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.
đ 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.
đ 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.
đ§Č 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.
đŻ 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 typesâmetals, non-metals, and metalloidsâwith 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.
Mindmap
Keywords
đĄPeriodic Table
đĄDmitri Mendeleev
đĄAtomic Number
đĄPeriodic Law
đĄGroups/Chemical Families
đĄMetals
đĄNon-Metals
đĄMetalloids
đĄAtomic Radius
đĄIonization Energy
đĄElectronegativity
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
[Music]
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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