What is the oxidation number of nitrogen in NH₄+?

• +1

• +3

• -3

• -1

The compound with the formula Na₂CO₃ is called

• Sodium carbonate

• Sodium hydrogen carbonate

• Sodium oxide

• Disodium trioxide

Which of the following is a trivalent element?

• Magnesium

• Aluminium

• Calcium

• Sodium

The IUPAC name for CaCl₂ is

• Calcium dichloride

• Calcium chloride

• Dicalcium chloride

• Calcium(II) chloride

The formula of the sulphate radical is

• SO₃²⁻

• SO₄²⁻

• HSO₃⁻

• SO₂

What is the electronic configuration of oxygen (atomic number 8)?

• 2,6

• 2,8

• 8

• 6,2

Which of the following ions has a valency of 1?

• SO₄²⁻

• NO₃⁻

• CO₃²⁻

• SO₃²⁻

The radical NH₄+ is known as

• Ammonium

• Ammonia

• Nitrite

• Nitrate

The IUPAC name of Fe₂O₃ is

• Iron oxide

• Iron(II) oxide

• Iron(III) oxide

• Ferric oxide

How many electrons are in the outermost shell of an atom with configuration 2,8,3?

• 2

• 3

• 5

• 8