Module 6: Lesson 1: Ion Formation Notes (pg 168)

​Module 6: Ionic Compounds and Metals (Notes)

Lesson 1: Ion Formation (pg 168)

By Catherine LaFever

Read with your copy of the notes and a high lighter!

Valence Electrons and Chemical Bonds

Chemical bond: a mutual electrical attraction between the nuclei and VALENCE electrons of different atoms that binds the atoms together. Another way to describe a chemical bond is to say the attractive forces between atoms or ions in compounds. In ionic compounds it is an attractive force between positive and negative IONS

Valence Electrons are the electrons in the atom’s outermost orbitals - generally the orbitals associated with the atoms highest principal energy level.

A. Electron Dot Structures:

Electron Dot Structures: show the placement and NUMBER of valence electrons. Rules to remember when drawing electron dot structures:

1. Only VALENCE electrons are shown. Valence electrons are the electrons in the OUTERMOST s and p sublevels. Transition metals could also have d sublevel valence electrons.

Multiple Choice

What are valence electrons?

• The total number of electrons in an atom

• The number of electrons in the outermost shell

• The number of electrons in the second shell

• The number of protons in the outermost shell

Multiple Choice

How many valence electrons are found in atoms of group 14?

• 4
• 3
• 14
• 16

Multiple Choice

How many valence electrons does Lithium (Li) have?

• 8

• 1

• 5

• 2

Multiple Choice

How many valence electrons does Selenium (Se) have?

• 6

• 16

• 79

• 34

A. Electron Dot Structures:

2. Valence electrons are shown as DOTS and are not drawn randomly! They are arranged around the element's SYMBOL to correspond to the element's electron configuration. (Only EIGHT dots or electrons per side.)

3. Follow the OCTET Rule which states that atoms form bonds in order to obtain 0 or 8 valence electrons, because of this electron dot structures will show no more than 8 electrons for each atom or ion. Another way to think of the Octet rule: Atoms react by changing the number of their electrons so as to acquire the stable electron configuration of a NOBLE gas.

Multiple Choice

Most elements will gain or lose electrons so that they end up with _______ valence electrons. (Except H and He)

• 2
• 6
• 8
• 10

B. Electron Dot Structure for Atoms:

Write the element's symbol and place the appropriate number of dots to represent the valence electrons around the symbol.

Try these three on your own

Multiple Choice

Which of these is correct?

Multiple Choice

This could be the dot diagram of 

• Ne
• Si
• Al
• Be

Multiple Choice

Which of the following is the correct electron dot structure for nitrogen?

In IONIC bonding valence electrons are actually TRANSFERRED between a nonmetal and metal. This happens because a non-metallic atom is much more ELECTRONEGATIVE and it can pull electrons away from the less electronegative metallic atom. In an ionic compound the positive and negative ions combine so that the overall charge is ZERO (0) .

Sometimes the more electronegative atom is not “powerful” enough to completely take away the electrons from another atom so the atoms SHARE electrons. This sharing of electrons is called a COVALENT bond.

B. Electron Dot Structure for Atoms:

Ionic Bonding occurs
between metals and nonmetals. 


Covalent Bonding occurs
between nonmetals.

In IONIC bonding valence electrons are actually TRANSFERRED between a nonmetal and metal. This happens because a non-metallic atom is much more ELECTRONEGATIVE and it can pull electrons away from the less electronegative metallic atom. In an ionic compound the positive and negative ions combine so that the overall charge is ZERO (0) .

Sometimes the more electronegative atom is not “powerful” enough to completely take away the electrons from another atom so the atoms SHARE electrons. This sharing of electrons is called a COVALENT bond.

B. Electron Dot Structure for Atoms:

Multiple Choice

The chemical bond between a non-metal and another non-metal will be a ________ bond.

• metal

• ionic

• covalent

• polar

Multiple Choice

The chemical bond between a metal and a non-metal will be a _____ bond.

• metal

• ionic

• covalent

• polar

Multiple Choice

Beryllium and sulfur will form a ______ bond

• ionic

• covalent

• metalloid

Multiple Choice

Carbon and Oxygen will make a ___________ bond.

• ionic

• covalent

• metallic

C. Formation of Ions:

C. Formation of Ions - Ions are formed when an atom has lost or gained valence electrons AKA: an atom with a CHARGE.

An atom will lose all its valence electrons or gain enough to have a completely full or empty outer energy level.

Pseudo-Noble Gas Configurations AKA THE OCTET RULE: Noble gas atoms are very stable & therefore don’t react or combine with other elements; they have 8 valence electrons (a “full” outer shell!)

C. Formation of Ions:

Octet rule: all representative elements will gain or lose (or share!) electrons to form an octet (8) of valence e- (Except H and He, who only have 2 valence electrons.)

• So, if an atom of Lithium had one valence electron, it is easier to lose one electron to go down to zero (or full on a lower energy level) than try to find seven electrons to fill its third energy level. It will become positive by one and have a +1 charge.

• Chlorine has seven valence electrons and will try to steal/gain an electron to create a full eight electrons in its energy level. It will become negative by one and have a -1 charge.

• Carbon in the middle could gain 4 or lose 4 electrons, but would be unlikely to form ions.

D. Positive Ion Formation:

Cations - these form when atoms have LOST valence electrons.

RULE: atoms with 3 or less valence electrons will
want to lose electrons to become stable.

To draw the dot structures, write the symbol, put [ ] around the symbol, and the charge of the ion outside the [ ]. There are NO dots because there are ZERO (0) valence electrons! (You may want to write the electron configuration for the atom to help you see what happens when it ionizes.)

D. Positive Ion Formation:

To draw the dot structures, write the symbol, put [ ] around the symbol, and the charge of the ion outside the [ ]. There are NO dots because there are ZERO (0) valence electrons! (You may want to write the electron configuration for the atom to help you see what happens when it ionizes.)

Multiple Choice

The positive ions tend to _____________ electrons.

• Share

• Lose

• Gain

• Neutral

Multiple Choice

If an element has 3 valence electrons, what charge will likely form on its ion ?

• +3
• +5
• -3
• -5

Multiple Choice

Which of the following will form a cation?

• Aluminum

• Sulfur

• Iodine

• Nitrogen

Multiple Choice

Which is the correct electron dot configuration for the Calcium ion?

E. Metal Ions:

Metals are reactive because they lose valence electrons easily. Groups ONE (1) /Alkali Metals and TWO (2) / Alkaline Earth Metals are the most reactive metals

F. Transition Metal Ions:

Transition metals can form ions with charges between 2 + and 5+ and their charges can be unpredictable. Transition metals may have multiple ions with different charges.

The highlighted transition metals are metals you will need to memorize the charges of.

Multiple Choice

Which of the following have a possible 4+ charge?

• Silver

• Manganese

• Cobalt

• Tin

Multiple Choice

Which of the have a possible 1+ charge?

• Copper

• Iron

• Manganese

• Nickel

Multiple Choice

What are the possible charges of Tin?

• Sn⁺ and Sn³⁺

• Sn²⁺ and Sn⁴⁺

• Sn²⁺ and Sn³⁺

• Sn⁺ and Sn²⁺

Multiple Choice

What are the possible charges of copper?

• Cu⁺ and Cu²⁺

• Cu⁺ and Cu³⁺

• Cu⁺ and Cu⁴⁺

• Cu²⁺ and Cu³⁺

G. Negative Ion Formation:

Anions-these form when atoms have GAINED valence electrons.

RULE: atoms with 5 or more valence electrons
will want to gain electrons to become stable

To draw the dot structures, write the symbol, draw 8 dots around the symbol, put [ ] around the symbol, and the charge of the ion outside the [ ]. (You may want to write the electron configuration for the atom to help you see what happens when it ionizes.)

To draw the dot structures, write the symbol, draw 8 dots around the symbol, put [ ] around the symbol, and the charge of the ion outside the [ ]. (You may want to write the electron configuration for the atom to help you see what happens when it ionizes.)

G. Negative Ion Formation:

G. Negative Ion Formation:

Non-Metals are reactive because they gain valence electrons easily. Groups SEVEN (7) Halogens are the most reactive non-metals

Multiple Choice

What is an anion's charge?

• positive

• negative

• neutral

• depends on the element's charge

Multiple Choice

Nonmetals form anions by gaining electrons to reach ______ electrons.

• 8

• 2

• 10

• 6

Multiple Choice

Group 16 elements form ______ ions.

• -2

• -1

• 0

• +2

Multiple Choice

What is the correct electron dot structure for the Chlorine Ion?

Practice: Write the complete electron configuration for the following ions and to the right, state if it is an anion or cation:

Practice: Write the complete electron configuration for the following ions and to the right, state if it is an anion or cation:

Multiple Choice

What electron configuration matches an oxygen atom?

• 1s²2s²2p⁶3s², 3p⁶4s²3d¹⁰4p⁵

• 1s²2s²2p⁴

• 1s²2s²2p⁶

• 1s²2s²2p⁶3s²3p⁶4s²3d¹

Multiple Choice

What electron configuration matches an oxygen ion?

• 1s²2s²2p⁶3s², 3p⁶4s²3d¹⁰4p⁵

• 1s²2s²2p⁴

• 1s²2s²2p⁶

• 1s²2s²2p⁶3s²3p⁶4s²3d¹

Multiple Choice

Which electron configuration belongs to a Chlorine (Cl) atom?

• 1s² 2s² 2p⁶ 3s² 3p⁵

• 1s² 2s² 2p⁶ 3s² 3p⁶

• 1s² 2s² 2p⁶ 3s² 3p⁷

• 1s² 2s² 2p⁶ 3p⁷

Multiple Choice

Which electron configuration belongs to a Chloride (Cl^-) ion?

• 1s² 2s² 2p⁶ 3s² 3p⁵

• 1s² 2s² 2p⁶ 3s² 3p⁶

• 1s² 2s² 2p⁶ 3s² 3p⁷

• 1s² 2s² 2p⁶ 3p⁷

Multiple Choice

What atom matches this electron configuration?
1s²2s²2p⁶

• Neon
• Magnesium
• Aluminum
• Potassium

Multiple Select

What ion(s) match/es this electron configuration?
1s²2s²2p⁶

• Neon
• Magnesium
• Aluminum
• Potassium