3.1.1 Periodicity

Question 1

periodicity definition

Answer 1

if the elements are arranged in an order the properties of elements would repeat after some period

Question 2

what does electronic structure determine

Answer 2

the chemical properties of each element

Question 3

why do elements in the same group have similar chemical properties

Answer 3

they have the same number of electrons on the outer shell

Question 4

ionisation energy definition

Answer 4

energy needed to remove 1 mole of outermost electrons from one mole of an element in the gaseous state

Question 5

what holds the electrons in an atom

Answer 5

electrostatic repulsion

Question 6

from what blocks are electrons lost from first

Answer 6

S and P

Question 7

what affects the magnitude of the ionisation energy

Answer 7

the number of protons in an atom

Question 8

1st ionisation energy equation for Na

Answer 8

Na -> Na+ +e-

Question 9

why does ionisation energy increase as you increase the number of protons

Answer 9

due to the positive charge on the nucleus increasing so the electrons are held tightly so more energy is needed to overcome them

Question 10

3 factors that affect ionisation energy

Answer 10

atomic radius
nuclear charge
electron shielding

Question 11

what happens to atomic radius as you go down a group or across a period

Answer 11

as you go down a group it increases
across a period it decreases

Question 12

what happens to nuclear charge as you go down a group and across a period

Answer 12

increases as there’s more protons in the nucleus

Question 13

what happens to electron shielding down a group and across a period

Answer 13

increases down a group and remains constant across a period

Question 14

how does shielding affect the ionisation energy down a group and across a period

Answer 14

increases across a period
decreases down a group

Question 15

why is the second ionisation energy of an element higher than the first

Answer 15

in the 1st ionisation they lose an electron so there’s less electrons than protons so the electrons are pulled closer to the nucleus so more energy is needed to remove the second electron

Question 16

successive ionisation energy definition

Answer 16

energy required to remove 1 electron after another

Question 17

what does the magnitude of the successive ionisation energy tell us

Answer 17

number of electrons in the outer shell
group the element is in
identity of the element

Question 18

what does the periodic trends in 1st ionisation energy provide evidence for

Answer 18

the existence of shells and sub-shells

Question 19

ionic bonding definition

Answer 19

metals and non metals losing and gaining electrons to form positive and negative ions held in an ionic lattice by forces of attraction

Question 20

covalent bonding definition

Answer 20

sharing of electrons to form electrostatic attraction between a shared pair of electrons and nuclei of the bonded atoms

Question 21

metallic bond definition

Answer 21

metals forming positive ions surrounded by a sea of delocalised electrons

Question 22

what determines the strength of a metallic bond

Answer 22

charge of the cation
size of cation
number of delocalised electrons

Question 23

what covalent structure are boron, carbon and silicon

Answer 23

giant

Question 24

why do giant covalent lattices have high melting points

Answer 24

due to the strong covalent bond requires high amounts of energy to overcome

Question 25

what makes a high ionisation energy

Answer 25

small radius
greater nuclear charge
less shielding
so makes a high nuclear attraction which requires lots of energy to overcome

Question 26

electronegativity definition

Answer 26

power of an atom to attract electron density from a covalent bond

Question 27

why is the 1st ionisation energy of oxygen less than nitrogen

Answer 27

as O has a new pair in the sub-shell so electron pair repulsion increases

Question 28

why is the first and second ionisation energy of strontium less than those of calcium

Answer 28

they are less than strontium as they have a larger atomic radius which causes increase in shielding they have a high nuclear charge but that’s outweighed by shielding and atomic radius so therefore nuclear attraction is weaker so less energy is required to remove outermost electron