3. Atomic Structure

Question 1

Atoms, Molecules, Ions

Answer 1

• An atom is a neutral particle of matter that uniquely defines a chemical element. Particles can be atoms, molecules or ions. Molecules are neutral particles made of two or more atoms bonded together. An ion is a positively or negatively charged particle.

Question 2

Answer 2

Made up of subatomic partices:

Question 3

Ions

Answer 3

• Cations are postively charged atoms or groups of atoms that have lost electrons
• Anions are negatively charged atoms or groups of atoms that have gained electrons

Question 4

Atomic & Mass No.

Answer 4

• Atomic number, represented by (Z), number of protons in atom
• Mass number (A) is the number of protons and neutrons in the nucleus

Question 5

Relative Atomic Mass

Answer 5

The relative atomic mass (Ar) is the average mass of atoms of an element relative to the mass of an atom of carbon-12 (which is given a mass exactly of 12).

Question 6

Isotopes

Answer 6

Same atomic number but different mass number so there are a different number of neutrons.

Question 7

Atomic Spectra

Answer 7

When atoms are excited (heat/flame) they are unstable at higher energy levels, and the electrons emit extra energy in the form of low energy wavelengths which correspond to the energy difference between shells. Because the excited atoms are unstable, tey

Question 8

Periodic Table

Answer 8

Question 9

Periodic Table Blocks

Answer 9

Question 10

Why do certain elements emit different colours when heated?

Answer 10

When we heat an atom, the electron gets excites and jump to higher energy levels. The ion is unstable and so electrons will return to lower energy levels. To do so, the electrons will emit energy in the form of light in different colours. These wavelengths correspond to the energy difference between the shells that the electrons will move.