3.1.1.3 Electron configuration- First ionisation energy Flashcards

1
Q

why the first ionisation energy of rubidium is less than the first ionisation energy of krypton

A
outer electron in Rb is in 5th shell (or additional shell) 
further away (or more shielded) from nucleus
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2
Q

Chemical equation for the enthalpy change: the first molar ionisation energy of silicon

A

Si(g) → Si+ (g) + e–

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3
Q

Chemical equation for the enthalpy change: the second molar ionisation energy of silicon

A

Si+ (g) → Si2+(g) + e–

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4
Q

reasons why the first ionisation energy of neon is lower than the third ionisation energy of magnesium

A

Mg2+ ion smaller than Ne atom / Mg2+ e – closer to nucleus

Mg2+ has more protons than Ne / higher nuclear charge

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5
Q

The general trend in the first ionisation energies of the Period 3 elements, Na – Ar

A

trend: increases
more protons / increased proton number / increased nuclear charge
same shell / same shielding / smaller size

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6
Q

why the first ionisation energy of sulphur is lower than would be predicted from the general trend of period 3 elements

A

e- pair in the 3p sub-level

repulsion between the e– in this e– pair

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7
Q

Definition: first ionisation energy

A

Energy to remove 1 electron

from a gaseous atom

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8
Q

why boron has a lower first ionisation energy than beryllium

A

Be’s outer electron is in an s (2s) orbital
B’s outer electron is in a p (2p) orbital
B’s outer electron is higher in energy

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9
Q

why the first ionisation energy of helium is very large

A

Electron is not shielded from nucleus

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10
Q

the general trend in the first ionisation energy of the Period 3 elements from Na to Ar

A

Increases

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11
Q

how, and explain why, the first ionisation energy of aluminium does not follow this general trend

A

lower than expected / lower than Mg / 1 less energy needed to ionise; e– removed from (3)p sub-level;
of higher energy / further away from nucleus / shielded by 3s e – s;

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12
Q

an equation, including state symbols, to represent the process for which the energy change is the first ionisation energy of Na

A

Na(g) → Na+ (g) + e–

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13
Q

the general trend in the values of the first ionisation energies of the elements Na to Ar

A
Trend : Increases
Explanation : Increased nuclear charge or proton number
Stronger attraction (between nucleus and (outer) e– )
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14
Q

how, and explain why, the values of the first ionisation energies of the elements Al and S deviate from the general trend

A

How values deviate from trend: (both values) too low
Explanation for Al: e– removed from 3p
e – or orbital is higher in energy level or better shielded than (3)s
or p electron is shielded by 3s electrons
Explanation for S: e– removed from (3)p electron pair (1) repulsion between paired e– (reduces energy required)

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15
Q

Definition: first ionisation energy

A

Heat / enthalpy / energy for removal of one electron (1) from a gaseous atom

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16
Q

Why the first ionisation energy of neon is higher than sodium

A

Neon’s electron is in a lower (2p) shell

attracted more strongly to (or less shielded from) the nucleus

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17
Q

Why the first ionisation energy of magnesium is higher than sodium

A

more protons
electrons in same shell
similar shielding

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18
Q

why the first ionisation energy of aluminium is lower than that of magnesium

A

Als outer electron is in a 3p sub-shell

higher in energy than 3s in Magnesium

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19
Q

the variation in first ionisation energy of the elements across Period 3 from sodium to argon

A

general increase across period
because number of protons (or nuclear charge) increases
but electrons in same shell (or similar shielding)
fall from Mg to Al
Al’s outer electron is in a p orbital
higher in energy than s electron in Mg
fall from P to S
two of the p electrons in S are paired (or in same orbital)

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20
Q

the trend in the first ionisation energies of the elements in Group 2 from magnesium to barium

A

Decrease
Ions get bigger / more (energy) shells
Weaker attraction of ion to lost electron

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21
Q

the element in Period 3 that has the highest first ionisation energy

A

Argon / Ar
Large(st) number of protons / large(st) nuclear charge
Same amount of shielding / same number of shells / same number of energy levels

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22
Q

an equation, including state symbols, to show the process that occurs when the first ionisation energy of rubidium is measured

A
Rb(g) → Rb+ (g) + e(–) 
OR Rb(g) + e(–) → Rb+ (g) + 2e(–) 
OR Rb(g) - e(–) → Rb+ (g)
23
Q

why the first ionisation energy of rubidium is lower than the first ionisation energy of sodium

A

Rb is a bigger (atom) / e further from nucleus / electron lost from a higher energy level/ More shielding in Rb / less attraction of nucleus in Rb for outer electron / more shells

24
Q

why the value of the first ionisation energy of sulfur is less than the value of the first ionisation energy of phosphorus

A

Paired electrons in (3)p orbital

repel

25
Q

the element in Period 2 that has the highest first ionisation energy

A

Neon/Ne

26
Q

an equation, including state symbols, to show the reaction that occurs when the first ionisation energy of lithium is measured.

A

Li(g) → Li+ (g) + e- (g)
Li(g) - e- (g) → Li+ (g)
Li(g) + e- (g) → Li+ (g) + 2e

27
Q

the general trend in first ionisation energies for the Period 3 elements aluminium to argon

A

Increases
Increasing nuclear charge / increasing no of protons
Same or similar shielding / same no of shells / electron (taken) from same (sub)shell / electron closer to the nucleus / smaller atomic radius

28
Q

how selenium deviates from this general trend in first ionisation energies for the Period 4 elements gallium to krypton

A

Lower
Paired electrons in a (4) p orbital
(Paired electrons) repel

29
Q

why the first ionisation energy of krypton is lower than the first ionisation energy of argon

A

Kr is a bigger atom / has more shells / more shielding in Kr / electron removed further from nucleus/ electron removed from a higher (principal or main) energy level

30
Q

Definition: first ionisation energy

A

Energy/enthalpy (needed) to remove one mole of electrons from one mole of atoms/compounds/molecules/elements 1
OR Energy to form one mole of positive ions from one mole of atoms
OR Energy/enthalpy to remove one electron from one atom
In the gaseous state (to form 1 mol of gaseous ions)

31
Q

the general trend in the first ionisation energies of the Period 3 elements sodium to chlorine

A

Increase
Bigger nuclear charge (from Na to Cl)/more protons
electron (taken) from same (sub)shell/similar or same shielding/ electron closer to the nucleus/smaller atomic radius

32
Q

How and why the element sulfur deviates from the general trend in first ionisation energies across Period 3

A

Lower
Two/pair of electrons in (3)p orbital
repel (each other)

33
Q

one element which deviates from the general trend in the first ionisation energies of the Period 2 elements lithium to fluorine

A

Boron/B or oxygen/O/O2

34
Q

Definition: first ionisation energy of an atom

A

enthalpy/energy change/required when an electron is removed/ knocked out / displaced/ to form a uni-positive ion
from a gaseous atom

35
Q

The Ne atom and the Mg2+ ion have the same number of electrons
reasons why the first ionisation energy of neon is lower than the third ionisation energy of magnesium

A

Mg2+ ion smaller than Ne atom / Mg2+ e– closer to nucleus

Mg2+ has more protons than Ne / higher nuclear charge or e – is removed from a charged Mg2+ion / neutral neon atom

36
Q

The general trend in the first ionisation energies of the Period 3 elements, Na – Ar

A

trend: increases
more protons / increased proton number / increased nuclear charge
same shell / same shielding / smaller size

37
Q

why the first ionisation energy of sulphur is lower than would be predicted from the general trend

A

the e– pair in the 3p sub-level

repulsion between the e– in this e–pair

38
Q

the general trend in the first ionisation energy of the Period 3 elements from Na to Ar

A

trend: increases

39
Q

How and why the first ionisation energy of aluminium does not follow this general trend

A
lower than expected / lower than Mg / 
less energy needed to ionise;
 e– removed from (3)p sub-level;
 (‘e– removed’ may be implied) o
f higher energy / further away from nucleus / shielded by 3s e–s
40
Q

Definition: first ionisation of an atom

A

Enthalpy change/required when an electron is removed/knocked out/displaced
From a gaseous atom

41
Q

why the value of the first ionisation energy of magnesium is higher than that of sodium

A

Increased/stronger nuclear charge or more protons

Smaller atom or electrons enter the same shell or same/similar shielding

42
Q

why the value of the first ionisation energy of neon is higher than that of sodium

A

Electron removed from a shell of lower energy or smaller atom or e– nearer
nucleus or e– removed from 2p rather than from 3s Less shielding

43
Q

Definition: first ionisation energy

A

Heat / enthalpy / energy for removal of one electron

from a gaseous atom

44
Q

an equation, including state symbols, to represent the process for which the energy change is the first ionisation energy of Na

A
Na(g) → Na+ (g) + e– 
OR Na(g) + e– → Na+ (g) + 2e–
45
Q

the general trend in the values of the first ionisation energies of the elements Na to A

A
Trend : Increases
Explanation : Increased nuclear charge or proton number
Stronger attraction (between nucleus and (outer) e– )
46
Q

how and why the values of the first ionisation energy of the element Al deviates from the general trend

A

too low
e– removed from (3) p
e – or orbital is higher in energy or better shielded than (3)s
or p electron is shielded by 3s electrons

47
Q

how and why the values of the first ionisation energy of the element S deviates from the general trend

A

too low
e– removed from (3)p electron pair
repulsion between paired e– (reduces energy required)

48
Q

Why the first ionisation energy of krypton is greater than that of bromine

A

Krypton has more protons than bromine

But its outer electrons are in the same shell (or have similar shielding)

49
Q

why the value of the first ionisation energy of magnesium is higher than that of sodium

A

Increased/stronger nuclear charge or more protons

Smaller atom or electrons enter the same shell or same/similar shielding

50
Q

Explain why the value of the first ionisation energy of neon is higher than that of sodium

A

Electron removed from a shell of lower energy or smaller atom or e– nearer
nucleus or e– removed from 2p rather than from 3s
Less shielding

51
Q

Explain why helium has a much higher first ionisation energy than lithium

A

He’s electron in 1s

closer to nucleus (or no shielding)

52
Q

why beryllium has a higher first ionisation energy than boron

A

Be’s outer electron in 2s

lower in energy than 2p

53
Q

why the first ionisation energy of krypton is greater than the first ionisation energy of bromine

A

more protons
or increased nuclear charge
attracting electrons in the same {shell/orbital/sub–shell/energy level
or similar shielding