Periodic table

Question 1

How are elements arranged in the periodic table?

Answer 1

By increasing atomic number.

Question 1

What is a period?

Answer 1

A horizontal row that shows the number of electron shells an atom has.

Question 2

What is a group?

Answer 2

: A vertical column that shows the number of outer electrons (valence electrons).

Question 3

What is valency?

Answer 3

The number of electrons an atom loses, gains, or shares to get a full outer shell.

Question 4

How do you predict ion charges from group number?

Answer 4

Metals lose electrons → positive ion = same as group number.

Non-metals gain electrons → negative ion = 8 minus group number.

Question 5

How can you tell the period of an element from its electronic configuration?

Answer 5

The number of electron shells = period.

Question 6

How can you tell the group of an element from its electronic configuration?

Answer 6

The number of outer electrons = group.

Question 7

Why do elements in the same group have similar chemical properties?

Answer 7

Why do elements in the same group have similar chemical properties?

Question 8

Reactivity trends:

Answer 8

Group I metals → more reactive down the group.
Group VII halogens → more reactive up the group.