Chap 4 F4

Question 1

Why is metal powder heated before the solid KMnO4?

Answer 1

so that the metal is hot and can burn quickly when O2 passes through it

Question 2

Group 1
change in m.p and bp
hardness
density

Answer 2

1. Decreases-weaker metallic bonding
2. decreases
3. Increses

Question 3

why size of atom decrease across the period

Answer 3

The proton number increases by one from one element to the next element.

This causes the positive charge of the nucleus
to increases.

• The force of attraction of the nucleus on the electrons of the first three shells increases.

The increase in the force of attraction of nucleus on the electrons causes the atomic size to decrease