Ch8 Periodic table and periodicity

Question 1

Periodic table arrangement of elements

Answer 1

1. by increasing atomic number
2. in periods showing repeating trends in physical and chemical properties
3. in groups have similair chemical properties

Question 2

periodicity

Answer 2

repeating pattern, in either physical or chemical properties, across different periods

Question 3

First ionisation energy

Answer 3

energy required to remove one electron from the ground state of each atom in one mol of gaseous atoms of that element to form one mol if gaseous 1+ ions

Question 4

Trend in first ionisation energy down a group

Answer 4

Decreases
- atomic radius increases
- shielding effect increases down group
- nuclear charge increases(outweighed by other factors)

Question 5

Trend in first ionisation energy across a period

Answer 5

General Increase
- atomic radius decreases
- nuclear charge increases
- shielding effect generally remains same

Question 6

Slight decrease in first ionisation energy

Answer 6

after 2nd and 5th element

elements in group 3- s electrons provide greater shielding of p electron, which is therefore lost more readily

elements in group 6- have pair of p electrons and repulsion is sufficient to make them ionise slightly more readily

Question 7

atomic radius

Answer 7

the further the electron is away from the nucleus the easier it is to remove an electron due to less attraction to nucleus

Question 8

nuclear charge

Answer 8

as number of protons in nucleus increases its attraction to outermost electrons increases

Question 9

shielding effect

Answer 9

electrons in inner shells exert repelling effect on outermost electrons in outer shell- reducing pull of nucleus on outer electrons