2.1.2 compounds, formulae and equations

Question 1

When are brackets used in writing formula?

Answer 1

Brackets are used if there is more than one polyatomic ion.

Question 2

What are polyatomic ions?

Answer 2

Ions with atoms of more than one element bonded together.

Question 3

What are cations?

Answer 3

Lose electrons to form cations-positive ions.

Question 4

What are anions?

Answer 4

Gain electrons to form anions-negative ions.

Question 5

What are binary compounds?

Answer 5

Binary compounds contain two elements only.
-change the element of the second elements to -ide.
(metal ion always comes first in ionic compounds).

Question 6

What are some common polyatomic ions?

Answer 6

NO3^- (nitrate)
CO3^2- (carbonate)
SO4^2- (sulphate)
OH^- (hydroxide)
NH4^+ (ammonium)
ZN^2+ (zinc (II) ion)
Ag^+ (silver (I) ion)