CHEMISTRY FORM 4 Chapter 2 & 3

Which of the following substances contain molecules?

• Zinc

• Ethanol

• Sodium chloride

• Magnesium oxide

The scientist who proposed that the atom consists of electrons orbiting around the nucleus is

• Ernest Rutherford

• James Chadwick

• J.J Thomson

• Neils Bohr

Isotopes are different atoms with the same number of

• protons, electrons and neutrons.

• electrons but different number of protons.

• protons but different number of neutrons.

• protons and neutrons but different number of electrons.

The nucleon number of sodium atom is 23 and its proton number is 11.

It follows that a sodium atom has

• 11 neutrons

• 11 electrons

• 12 protons

• 23 neutrons

Oxygen and oxide ions

• are isotopes of oxygen

• are chemically identical.

• have the same number of protons.

• have the same number of electrons.

The boiling point of pentane is 36^oC. Which of the following statements is true about the molecules of pentane at 40^oC?

• The pentane molecules become lighter.

• The kinetic energy of the pentane molecules is lower.

• The distance between pentane molecules increases.

• The attraction force of the pentane molecules becomes stronger.

Which of the following elements has the greatest number of valence electron?

• Helium

• Sulphur

• Fluorine

• Potassium

Chlorine has an atomic number of 17 and has 18 neutrons. What is it mass number?

• 35

• 18

• 17

• 1

Subatomic particle with no charge

• proton

• neutron

• electron

• nucleus

Which of the following statements is NOT true of all different types of matter?

• They are made of atoms and molecules
• The particles are always in motion
• The particles always move at the same speed
• They are made of particles that are too small to see