Unit 5 Chemistry Review

A positive ion is formed when a neutral atom:

•  loses electrons 

• gained electrons

• gains protons

Elements that usually need to gain electrons to become stable ions are:

• metals

•  alkali metals

• nonmetals

 Fluorine mostly forms which ion?

• F+

• F2+

• F-

When K and S react to form an ionic bond, what happens?

•  K will lose an electron

• K will gain electrons

• S loses electrons

Which is NOT a property of an ionic compound?

• have high melting points

• not brittle

• conducts electricity when dissolved in water

Which elements form an ionic compound?

• Mg and Cu

• Cs and O

• Fe and Co

What happens in an ionic bond?

•  oppositely-charged (+ -) ions attract

•  two atoms share more than two electrons

• ions with the same charge (++ or - -) attract

Element X  is in group 2, and element Y  is in group 7 of the periodic table.

Which ions will be in the compound when X and Y react together?

• X+ and Y2-

• X2+ and Y- 

• X2- and Y+

An ionic compound forms between an element X from group 2 and an element Y from group 6. 

What is the formula?

• XY

• XY2

•  X2Y

When calcium reacts with oxygen, what is the formula of the ionic compound?

• CaO

• CaO2

• Ca2O