Chemistry Bonding Unit Review

Ionic and Covalent Bonding

Why do atoms form bonds?

Why do chemical bonds form?

• Atoms form bonds when their valence electrons interact.

• What are valence electrons?

• Atoms join to form bonds so that each atom has a stable electron configuration.

• Each atom binds in order to fill its outermost energy levels.

Open Ended

Why do atoms join to form bonds?

Valence electrons are the outer electrons on an atom!

In the picture to the right there are 2 electrons

Multiple Choice

Valence electrons are:

• Electrons farthest away from the nucleus

• Electrons closest to the nucleus

• Electrons that just come and go - they don't stay with the atom

• Electrons in the second shell

Multiple Choice

How many valence electrons does Nitrogen Have?

• 1 Valence electron

• 2 Valence electron

• 3 Valence electron

• 4 Valence electron

• 5 Valence electron

Multiple Choice

How many valence electrons does Hydrogen Have?

• 1 Valence electron

• 2 Valence electron

• 3 Valence electron

• 4 Valence electron

• 5 Valence electron

Multiple Choice

Which group has the greatest number of valence electrons?

• 1

• 14

• 18

• 16

Multiple Choice

USE THE PERIODIC TABLE

How many valence electrons does carbon have?

• 4

• 12

• 6

• 14

Multiple Choice

How many valence electrons are found in atoms of Iodine?

• 4
• 7
• 9
• 1

Multiple Choice

How many valence electrons are in an atom of K?

• 3
• 8
• 4
• 1

COMPOUNDS

• A compound is formed when two or more elements chemically bond together.

• The properties of compounds are different from the properties of the elements that make them.

• Example:

  The properties of water (a liquid) are different from the properties of hydrogen (a gas) and oxygen (a gas).

• Compounds use chemical names (e.g. Carbon dioxide) and are represented by a chemical formula (e.g. CO₂)

Multiple Choice

Element or compound?

H₂O

• element

• compound

Multiple Choice

How many atoms of carbon (C) are in C₆H₁₂O₆?

• 3
• 6
• 12
• 24

Multiple Choice

Element or Compound?

Na

• Element

• Compound

Multiple Choice

Element or Compound?

NaCl

• Compound

• Element

Multiple Choice

Formula for barium sulfide

• B₂S₃

• BaS

• Ba₂S

• BaS₂

Multiple Choice

Which of the following is a group of compounds?

• O, N, P

• NaCl, H₂O, CH₄

• both are correct

Multiple Choice

A compound is a combination of ________ or more elements.

• one

• two

• three

• four

Ionic bond

• the bonding between a non-metal and a metal, that occurs when charged atoms (ions) attract

• structure is a network of bonded ions

• valence electrons are transferred

• Electrical conductivity is good when melted/dissolved

• Solid at room temperature; high melting and boiling points

Multiple Choice

Ionic bonds are formed between...

• Non - metals

• A metal and a non-metal

• Metals

Multiple Choice

An ionic bond is the attraction between:

• oppositely charged ions

• similarly charged ions

• neutral ions

• neutral atoms

Multiple Choice

Why do ionic bonds form?

• So the number of protons equals the number of electrons.
• To stabilize the atom with a full outer shell.
• So an atom can become unstable.
• So atoms will stick together to form molecules.

Multiple Choice

How is an ionic bond formed?

• Sharing of electrons

• Delocalised electrons

• Transfer of electrons

Multiple Choice

An example of an ionic compound is Sodium Chloride, which is made from Na⁺ and Cl^- ions. Why do these ions form an ionic bond?

• They have like charges

• They are from the same group

• They are from the same period

• They have opposite charges

Covalent Bond

• a chemical bond formed between nonmetal atoms when electrons are shared between two atoms.

• structure of molecules

• valence electrons are shared

• poor electrical conductivity and can be a solid, liquid, or gas at room temperature

• has low melting and boiling points

Multiple Choice

A covalent bond forms when atoms ___________ electrons.

• gain

• share

• increase

• transfer

Multiple Choice

How are covalent bonds explained?

• When one atom takes the other atom's electron

• When the atom shares an electron with an another atom

• When the two nucleus merge

• When the neutrons leave the nucleus

Multiple Choice

What two types of atoms make a covalent bond?

• 2 Nonmetals

• 1 Nonmetal and 1 Metal

• 2 Metals

• 2 Noble Gases

Multiple Choice

Molecules

• Ionic compounds

• Covalent compounds

Multiple Choice

Network of bonded ions

• Ionic bonds

• Covalent bonds