periodicity

Question 1

Who created the periodic table arrangement?

Answer 1

Dmitri Mendeleev

Question 2

a row

Answer 2

period

Question 3

a column

Answer 3

group

Question 4

noble gases

Answer 4

unreactive non-metals, gases at room temperature, monatomic

Question 5

halogens

Answer 5

very reactive non-metals, coloured

Question 6

alkali earth metals

Answer 6

fairly reactive metals

Question 7

alkali metals

Answer 7

very reactive metals, usually stored under oil to prevent reaction with oxygen and water vapour in the air

Question 8

transition metals

Answer 8

metals often used as catalysts

Question 9

melting point

Answer 9

increases across a period and decreases down a group

Question 10

boiling point

Answer 10

increases across a period and decreases down a group

Question 11

density

Answer 11

increases across a period, decreases down a group

Question 12

covalent radius

Answer 12

a measure of the size of an atom, half the distance between the nuclei of 2 of its bonded atoms

Question 13

covalent radius across a period

Answer 13

decreases due to increased nuclear charge of the atoms, energy levels of electrons more strongly attracted to the positive nucleus

Question 14

covalent radius in a group

Answer 14

increases as there is an increase in the number of electron shells which makes the atom bigger

Question 15

ionisation energy

Answer 15

the first ionisation energy of an element is the energy required to remove one mole of electrons from one mole of gaseous atoms.

Question 16

ionisation energy across a period

Answer 16

increases, more energy required ro remove electron as there is an increased nuclear charge, also atoms getting smaller therefore electron is closer held to the nucleus.

Question 17

ionisation energy down a group

Answer 17

decreases, less energy required to remove outer electron as it is further from the nucleus, also screening effect as more shells of electrons between the electron and nucleus.

Question 18

second ionisation energy

Answer 18

the energy required to remove the second mole of electrons

Question 19

electronegativity

Answer 19

a measure of the attraction an atom has for bonding electrons (i.e. how tightly the atom holds on to bonding electrons)

Question 20

electronegativity across a period

Answer 20

increases, increasing nuclear charge pulls electrons closer to nucleus and greater ability to share electrons, smaller radius means outer electrons are more strongly held, more energy required

Question 21

electronegativity down a group

Answer 21

decreases as increasing number of electron shells makes the atom bigger, increased shielding means outer electrons are less strongly held, less energy required