1.2 The Periodic Table

Question 1

How are elements arranged in the periodic table?

Answer 1

Order of atomic number

So elements with similar properties are in columns

Question 2

What are colums of elements known as in the periodic table?

Answer 2

Groups

Question 3

What do elements in the same group have in common?

Answer 3

Same number of electrons in their outer shell
Similar chemical properties

Question 4

What is the law of octaves?

Answer 4

In Newlands periodic table, elements were ordered by weight

Similar properties occured every 8th element - stopped after calcium

Question 5

How did Mendeleev order his periodic table?

Answer 5

Atomic mass

Did change order based on atomic weight (takes account of isotopes)

Trends, so he left gaps when elements did not react similarly, therefore predicting elements

Question 6

How is the modern periodic table ordered?

Answer 6

Atomic number

Elements were then placed in groups

Question 7

What are group 1 elements called?

Answer 7

Alkali metals

Question 8

What do all group 1 elements have in common?

Answer 8

Single electron in their outer shell

Question 9

How do group 1 elements react with water?

Answer 9

Vigorously to create an alkaline solution and hydrogen

Question 10

How do group 1 metals react with oxygen?

Answer 10

All react to create an oxide

Question 11

How do group 1 elements react with chlorine?

Answer 11

All react forming a white precipitate

Question 12

What happens to reactivity of group 1 elements as you go down the group?

Answer 12

Reactivity increases

This is because the electron in the outermost shell becomes further from the positive nucleus, so there is less attraction to the nucleus

As there is less attraction, it can be easily pulled away

Question 13

LEARN THIS TABLE

Answer 13

Question 14

What are group 0 elements called?

Answer 14

Noble gases

Question 15

How many electrons do noble gases have in their outer shell?

Answer 15

All have 8 except helium that has 2

All of their shells are completely full

Question 16

Why are group 0 elements not very reactive?

Answer 16

They have a full outer shell, so they have a stable arrangement of electrons

Question 17

What happens to the boiling point of group 0 elements as you go down the table?

Answer 17

Increases due to increasing atomic mass

Question 18

What are group 7 elements called?

Answer 18

The Halogens

Question 19

How many electrons do group 7 elements have in their outer shell?

Answer 19

7

Question 20

Why do group 7 elements exist as pairs e.g. Cl2

Answer 20

They share electrons to have a complete set of pairs

Question 21

What happens as you go down group 7?

Answer 21

Increased:
- Molecular mass
- Melting point
- Boiling point

Question 22

Why does reactivity decrease as you go down group 7?

Answer 22

Halogens react by gaining an electron

As you go down the group there are more electrons further from the nucleus, so there is less attraction to the positive nucleus

So negatively charged electrons are less drawn to the positively charged nucleus as it is further away

Question 23

If elements decrease in reactivity, what does this mean for displacement?

Answer 23

Elements higher up in the group will displace elements that are lower down

So chlorine will displace bromine e.g.

Chlorine + Potassium bromide -> Potassium chloride + Bromine