8 - Unit 1, Section 1 - Day 4

Atoms and Elements: A Review

Unit 1, Section 1

Multiple Choice

We reviewed adding and subtracting negative numbers in today's Bellringer. Which of the three subatomic particles are we most likely learning about today?

• Proton

• Neutron

• Electron

• Protons and electrons are balanced in an atom

  • That means there are an equal number of protons and electrons

• Atoms are neutral (they have zero charge

Atoms - Balanced Protons and Electrons

• Ion - An atom that has an electric charge

  • They can be positive or negative

• Ions form when there are an unequal number of protons and electrons

Ions

• Ions form when an atom either loses or gains electrons

• Atoms do not lose or gain protons to form ions

How do Ions form?

• Negative ions

• Formed when atoms gain electrons

Anions

• Positive ions

• Formed when atoms lose electrons

Cations

The Two Types of Ions

The Charge of An Ion

An ion's charge is determined by how many electrons it loses or gains

​Electron Change	​Charge
​Loses 4	​+4
Lose​s 3	+3​
Loses 2	+2​
​Loses 1	+ 1
Gains 1​	-​ 1
Gains 2​	-2​
Gains 3​	-3​
Gains 4​	-4​

Multiple Choice

An atom loses 3 electrons: the cation that forms now has a charge of:

• +4

• +3

• -3

• -4

Multiple Choice

An atom gains two electrons. The anion that forms has a charge of:

• +3

• +2

• -2

• -3

Ionic Charge and The Periodic Table

Ionic Bonding - the attraction between a positive cation and a negative anion

• This attraction is in three dimensions

• A crystal forms with alternating cations and anions

Ionic Bonding

Ionic bonding usually happens when a metal and a nonmetal interact

• The metal loses electrons and becomes a cation

• The nonmetal gains electrons and becomes an anion

• The cation and anion are attracted to each other and form a crystal

Ionic bonding and the Periodic Table

Multiple Choice

Barium (Ba) will lose two electrons to become:

• A cation with a charge of +1

• A cation with a charge of +2

• An anion with a charge of -1

• An anion with a charge of -2

Multiple Choice

Iodine (I) will gain one electron to become:

• A cation with a charge of +1

• A cation with a charge of +2

• An anion with a charge of -1

• An anion with a charge of -2

Multiple Choice

Ionic bonding usually happens between:

• Two metals

• A metal and a nonmetal

• Two nonmetals

Multiple Select

(CHOOSE BOTH) Which two compounds are most likely formed from ionic bonding?

• PbCl₂

• HC₂H₃O₂

• N₂O₇

• Fe₂O₃