Chemical Bonding and Reactions

The chemical bond formed when two atoms share electrons is called a(n)_____.

• Covalent Bond

• Ionic Bond

• Metallic bond

• Electron bond

Which pair of atoms will combine with each other and form an ionic bond?

• C and O

• C and H

• Ca and Mg

• Ca and Br

Answer explanation

Ionic bonds are between a metal and a non-metal

Which element is most likely to gain electrons in a chemical reaction?

• Kr

• K

• Br

• Ca

Answer explanation

Br is a non-metal which becomes an anion with a negative charge - it gained electrons

What is the oxidation number of oxygen in most compounds?

• 6

• -2

• 8

• 0

Answer explanation

Oxidation numbers are the number of electrons gained or lost.

Oxygen need to gain two electrons in order to have 8.

Which formula represents a substance that contains covalent bonds?

• LiCl

• CaCl₂

• K₂O

• CO₂

Answer explanation

Covalent bonds are between non-metals (right side of staircase) only

How does an atom of aluminum become and ion?

• It gains 3 electrons

• It gains 3 protons

• It loses 3 electrons

• It loses 3 neutrons

Which atoms are most likely to form covalent bonds?

• metal atoms that share electrons

• metal atoms that share protons

• nonmetal atoms that share electrons

• nonmetal atoms that share protons

The electrons that are lost, gained or shared in chemical bonds are called.

(a)  

• valence electrons
• chemical electrons
• Lewis electrons
• None of the above

Which process is taking place in the picture?​ ​ (a)   ​ (b)  

• electron sharing
• covalent bond

How many electrons are needed in the outer energy levels of most atoms for the atom to be chemically stable?

Answer explanation

8 electrons (Nobe Gas Configuration)