What Are Ions | Properties of Matter | Chemistry | FuseSchool

Summary

This educational lesson introduces the concept of ions, which are atoms or molecules with a net electric charge due to the gain or loss of electrons. It explains that positively charged ions, called cations, are formed when atoms lose electrons, while negatively charged ions, known as anions, are created when atoms gain electrons. The lesson uses Na (sodium) and O (oxygen) as examples to illustrate how ions achieve a stable electronic structure similar to noble gases, with metals typically forming cations and non-metals forming anions. It also touches on the common charges of ions from different groups in the periodic table.

Takeaways

• 🔬 Ions are atoms or molecules that have gained or lost electrons, resulting in a net electrical charge.
• ⚡ Electrons carry a negative charge, so when an atom loses electrons, it becomes positively charged (a cation), and when it gains electrons, it becomes negatively charged (an anion).
• 🐱 The term 'cation' can be remembered with the mnemonic 'cats have paws', associating the positive charge with the word 'cation'.
• 📚 The electronic structure of an atom is often represented with the number of electrons in each shell, and the valence shell is the outermost shell.
• 📝 When writing the formula of an ion, the charge is indicated as a superscript.
• 📐 For drawing electronic structures, the atom or ion is enclosed in square brackets with the charge written in the top right corner.
• 🌀 Ions tend to have a complete outer shell similar to that of a noble gas, which is a stable electronic configuration.
• 🤔 The lesson encourages self-practice by asking the learner to draw the electronic structures of Ca and Cl, which form ions by losing and gaining electrons, respectively.
• 🧩 Metals, particularly those in Group 1 and 2, tend to lose electrons to form cations with +1 and +2 charges.
• 💧 Non-metals like oxygen and fluorine gain electrons to form anions with -2 and -1 charges, respectively.
• 🔑 Group 3 elements, such as aluminum, form ions with a +3 charge by losing three electrons, while Group 5 elements, like nitrogen, gain three electrons to form ions with a -3 charge.
• 🔍 Group 4 elements, including carbon, are noted for their tendency to form covalent compounds rather than ionic ones, which is a topic for further exploration.

Q & A

What is an ion?

An ion is a charged particle that is formed when an atom gains or loses electrons.

What happens when an atom loses electrons?

When an atom loses electrons, it becomes positively charged and is called a cation.

What is the term for a positively charged ion?

A positively charged ion is called a cation.

How can you remember the term 'cation'?

You can remember 'cation' by associating it with 'cats' and 'paws', which both start with a 'c' and 'p' respectively.

What happens when an atom gains electrons?

When an atom gains electrons, it becomes negatively charged and is called an anion.

What is the term for a negatively charged ion?

A negatively charged ion is called an anion.

What is the electronic structure of Na before it becomes an ion?

The electronic structure of Na (sodium) before it becomes an ion is 2, 8, 1.

How does the electronic structure of Na change when it becomes an ion?

When Na loses its one valence electron, it becomes a positively charged Na+ ion.

What is the electronic structure of O before it becomes an ion?

The electronic structure of O (oxygen) before it becomes an ion is 2, 6.

How does the electronic structure of O change when it becomes an ion?

Oxygen gains two electrons to form a negatively charged O2- ion.

Why do ions form the same electronic structure as a noble gas?

Ions form the same electronic structure as a noble gas because they achieve a stable configuration by filling their outer shell, similar to the noble gases.

What is common between Na and Mg in terms of ion formation?

Both Na (sodium) and Mg (magnesium) are metals that lose their valence electrons to form cations with a +1 and +2 charge respectively.

Why do non-metals like O and F tend to form anions?

Non-metals like O (oxygen) and F (fluorine) tend to form anions because they gain electrons to achieve a stable electronic configuration similar to that of a noble gas.

What charge does an oxygen ion typically have?

An oxygen ion typically has a -2 charge because it gains two electrons to fill its valence shell.

What charge does a fluorine ion typically have?

A fluorine ion typically has a -1 charge because it gains one electron to fill its valence shell.

How does the group number of an element relate to the charge of its ion?

The group number of an element often indicates the number of valence electrons it has and thus the charge of the ion it forms. For example, Group 1 metals form +1 ions, and Group 2 metals form +2 ions.

What is the charge of an ion formed by an element from Group 3?

An element from Group 3, such as aluminium, forms an ion with a +3 charge by losing three electrons.

What is the charge of an ion formed by an element from Group 5?

An element from Group 5, such as nitrogen, forms an ion with a -3 charge by gaining three electrons.

Why do Group 4 elements like carbon tend to form covalent compounds?

Group 4 elements like carbon tend to form covalent compounds because they share electrons to achieve a stable electronic configuration rather than gaining or losing electrons to form ions.