Trends in the periodic table

Question 1

what are the trends in the periodic table

Answer 1

valence electrons, number of electron shells, atomic radius, electronegativity, first ionisation energy and metallic properties

Question 2

what is effective nuclear charge

Answer 2

aka core charge is a measure of the attractive force felt by the valence shell electrons to the nucleus

Question 3

how to calculate effective nuclear charge

Answer 3

number of protons - number of total inner-shell electrons

Question 5

effective nuclear charge down a group

Answer 5

remains constant but valence electrons are held less strongly as they are further away from the nucleus

Question 6

effective nuclear charge across a period

Answer 6

increases, group is equal to effective nuclear charge

Question 7

electronegativity

Answer 7

the ability of an atom to attract electrons towards itself when forming a chemical bond, a measure of how strongly an atom pulls on the electrons of nearby atoms

Question 8

when does electronegativity not apply

Answer 8

for the noble gases group 18, because the elements have a stable outer shell and wont readily form bonds

Question 9

trend in electronegativity down a group

Answer 9

decreases as shell number increases so electrons are less attracted to the nucleus

Question 10

trend in electronegativity across a period

Answer 10

increases are no. of shells remain constant but effective nuclear charge increases

Question 11

atomic radius

Answer 11

the measurement used for the size of atoms, it can be regarded as the distance from nucleus to the valence shell electrons

Question 12

trend in radius down a group

Answer 12

increases as effective nuclear charge remains constant and shell number increases

Question 13

trend in atomic radius across a period

Answer 13

decreases as shells remain constant and effective nuclear charge increases, pulling valence shell electrons in more tightly

Question 14

first ionisation energy

Answer 14

the energy required to remove one electron from an atom of an element

Question 15

how does one electron being removed occur

Answer 15

when an element is heated, its electrons can move to higher energy shells, if given enough energy an electron can be completely removed, becoming a positive ion

Question 16

what does first ionisation energy indicate

Answer 16

how strongly the valence electrons are attracted to the nucleus, the stronger the attraction, the more energy required to remove one

Question 17

trend in first ionisation energy down a group

Answer 17

decreases as effective nuclear charge remains constant, number of shells increases, they are further from the nucleus so less energy is required to remove an electron

Question 18

trend in first ionisation energy across a period

Answer 18

increases as effective nuclear charge increases and shells remain constant, electrons are strongly attracted to nucleus so harder to remove

Question 19

what can the knowledge of whether as element is a metal, nonmetal or metalloid help to predict

Answer 19

how the element will react and bond with other elements

Question 20

reactivity of metals as you go down a group

Answer 20

increases as valence electrons are further away from the pull of the nucleus and can be lost more easily

Question 21

reactivity of metals across a period

Answer 21

effective nuclear charge increases so metals become less reactive

Question 22

what is the most reactive metal

Answer 22

francium, bottom left corner

Question 23

reactivity of non-metals as you go down a group

Answer 23

decreases as effective nuclear charge remains constant but shells increase which causes electrons to be less electronegative so dont pull electrons in as much

Question 24

reactivity of non-metals across a period

Answer 24

increases as effective nuclear charge increases and shells remain constant

Question 25

most reactive non-metal

Answer 25

top right fluorine