Structure 3.1

Question 1

periodicity

Answer 1

repeating trends in the physical and chemical properties of elements across a period and down a group

Question 2

which two transition metals have a 4s1 electron configuration?

Answer 2

copper
chromium

Question 3

nuclear charge

Answer 3

the positive charge possessed by the nucleus of an atom (i.e. number of protons in the nucleus of an atom)

Question 4

trend of nuclear charge down a group

Answer 4

increases, as there are more protons in the nucleus of successive elements down the group

Question 5

trend of nuclear charge across the periodic table (i.e. from left to right)

Answer 5

increases, as there are more protons in the nucleus of each successive element across the grou

Question 6

shielding

Answer 6

the reduction in attractive force experienced by electrons in the valence shell due to the presence of inner shell electrons

Question 7

trend of shielding effect down a group

Answer 7

increases, as the number of occupied electron shells increases, increasing the shielding effect

Question 8

trend of shielding effect across a group

Answer 8

remains constant, as electrons are only added to the valence shell. the number of inner electrons constant. therefore, the shielding effect is constant.

Question 9

effective nuclear charge

Answer 9

attractive force experience by the electrons in the valence shell

Question 10

approximation of effective nuclear charge (equation)

Answer 10

ENC = nuclear charge - number of shielding electrons

Question 11

what can explain trends in physical properties in the periodic table

Answer 11

effective number charge
number of occupied electron shells (i.e. distance of the valence shell from the nucleus)
repulsion between electrons

Question 12

what is the trend in effective nuclear charge down a group?

Answer 12

remains the same

Question 13

what is the trend in effective nuclear charge across a group?

Answer 13

increases. number of protons increase, but number of shielding electrons remain the same therefore, the effective nuclear charge will increase

Question 14

properties of elements which show periodicity

Answer 14

atomic radii
ionisation energy
electron affinity
electronegativity
ionic radius

Question 15

atomic radius

Answer 15

distance from the nucleus to the valence shell of an atom

Question 16

how is atomic radii measured

Answer 16

half the distance between neighbouring nuclei of the same element

Question 17

trend of atomic radii down a group

Answer 17

increases. effective nuclear charge remains constant down a group. more electron shells are occupied. therefore, the distance between valence electrons and the nucleus increases

Question 18

trend in atomic radii across a period

Answer 18

decreases. effective nuclear charge increases with each successive element. number of shielding electrons (