Periodic table trends

Question 1

define atomic radius

Answer 1

average distance between outermost electron and nucleus

Question 2

ionisation energy

Answer 2

amount of energy required to lose 1 mol of outermost electrons from 1 mol of an element in its gaseous phase

Question 3

electronegativity

Answer 3

electron attracting ability of the element

Question 4

core charge

Answer 4

electrostatic attraction between the valence electrons and nucleus

Question 5

down a group –> atomic radius

Answer 5

• additional shell further from the nucleus
• increase distance between outermost electron and nucleus
• increase atomic radius

Question 6

across a period –> atomic radius

Answer 6

• additional number of protons, same number of inner shell electrons, =shielding effect
• increased core charge –> electrostatic attraction between nucleus and valence electrons
• increased electrostatic attraction between nucleus and valence electrons, which includes outermost electron
• outermost electron closer to radius
• smaller atomic radius

Question 7

down a group –> electronegativity

Answer 7

• additional shell further away from the nucleus
• increase distance between nucleus and outermost electron
• increase atomic radius
• incoming electron is not able to approach the nucleus as closely
• weaker electrostatic attraction between nucleus and incoming electron
• decreased electron attracting ability of element
• decreased electronegativity

Question 8

across a period –> electronegativity

Answer 8

• increased number of protons, same number of inner shell electrons = shielding effect
• increased core charge –> increase electrostatic attraction between nucleus and valence electrons, including outer most electron
• decrease distance between outermost electron and nucleus
• decrease atomic radius
• incoming electron able to approach the nucleus more closely
• increase electrostatic attraction between incoming electron and nucleus
• increased electron attracting ability of element
• increase electronegativity

Question 9

down a group –> ionisation energy

Answer 9

• additional shell further away from nucleus
• increase distance between outermost electron and and nucleus
• weaker electrostatic attraction between outermost electron and nucleus
• less energy needed to remove outermost electron
• decrease ionisation energy

Question 10

across a period –> ionisation energy

Answer 10

• increased number of protons, equal number of inner shell electrons, = shielding effect
• increase core change, increase electrostatic attraction between nucleus and valence electrons, including outermost electron
• increase energy needed to remove outermost electron
• increase ionisation energy

Question 11

gradual increase in successive ionisation energy

Answer 11

• as electrons are lost from an atom/ion
• core charge is distributed over less electrons
• increased energy needed to remove subsequent electrons

Question 12

marked increase in successive ionisation energy

Answer 12

• as electrons are removed from a shell closer to nucleus
• much stronger electrostatic attraction between electron and nucleus
• marked energy increase to remove subsequent electrons

Question 13

relative atomic mass

Answer 13

weighted average of the masses of all the isotopes of an element relative to carbon-12