Atoms, Elements and Compounds

In an atom, what is the number of protons equal to?

• The number of electrons

• The number of neutrons

• The number of nuclei

• The number of molecules

Particles in an atom that are neutral and have no charge are

• negatrons

• protons

• neutrons

• electrons

Which element exists as a macromolecule ?

• Oxygen

• Carbon

• Sodium

• Hydrogen

Which statement is not correct ?

• Ammonia is a compound.

• Methane is a compound.

• Air is a mixture.

• Sea water is a compound.

Which of the following is not a mixture ?

• Tap water

• Petrol

• Ethanol

• Steel

Which compound contains three elements ?

• Aluminium chloride

• Iron(III) oxide

• Sodium carbonate

• Potassium oxide

Which particle contains most electrons ?

• O^3-

• Ne

• Na^-

• Mg³⁺

Which ions has the most shells that contain electrons ?

• N^3-

• Al³⁺

• Be²⁺

• S^2-

Which substance, when molten, conducts electricity ?

• bitumen

• caesium iodide

• diamond

• sand

Which of these does not exist as a diatomic molecule ?

• Neon

• Chlorine

• Hydrogen

• Oxygen