Periodic Table

Question 1

Metalloids

Answer 1

Elements that exhibit both the properties of metals and non-metals.

Question 2

Metallic character

Answer 2

Ease at which the atom of an element forms a positive ion through the loss of electron

Question 3

Metallic character decreases across a period

Answer 3

The number of protons in the nucleus increases while the number of electron shells remain the same. The attraction by the nucleus for the valence electrons increases hence leading to a decrease in the ease at losing these valence electrons

Question 4

Metallic character increases down a group

Answer 4

The number of electron shells increases, the valence electron are further away from the nucleus and the force of attraction on these valence electrons by the protons in the nucleus decreases. The valence electrons are more easily lost, thus metallic character increases

Question 5

Valency

Answer 5

Number of valence electrons used by an atom during bonding

Question 6

Physical properties of Group I metals

Answer 6

1. They are generally soft and can be cut easily.
2. They have relatively low density compared to other metals, density increases down the group.
3. They have a relatively low melting point. Melting point decreases down the group as the molecular size increases, the nucleus is further away from the sea of delocalised electrons, hence a weaker electrostatic forces of attraction between the cation and the sea of delocalised electrons

Question 7

Physical properties of halogen

Answer 7

1. Low melting and boiling point
   They have simple molecular structures, little energy is needed to over come the weak intermolecular forces of attraction between the halogen molecules.

Melting point increases down the group
Down the group, the number of electrons increases more energy is required to overcome the stronger intermolecular forces of attraction.

2. They do not conduct electricity
   They dk not have mobile electrons or ions to act as mobile charge carriers.
3. All halogens are coloured

Question 8

Characteristics or Transition metals

Answer 8

1. High density
2. Variable oxidation states
3. Form coloured compounds
4. Good catalysts