7.1 & 7.2 the periodic table and Ionisation energies

Question 1

The development of the periodic table…

Answer 1

Aristotle:everything was
made of 4 elements, earth, water, air and fire.
Döbereiner:‘law of triads’ Cl Br I
John Newlands:devise a Periodic Table of the elements arranged in order of their relative atomic masses. ‘Law of octaves.’
Mendeleevarranged the elements in increasing
mass order but left ‘gaps’

Question 2

The Modern Periodic Table is arrangged in increasing….

Answer 2

atomic number

Question 3

periodic table

groups share similar …… properties because…..

Answer 3

Elements in the same group
have similar** chemical properties **as they have the same no. of electrons on the outer shell.

Similar elements are placed in vertical groups so any element within a group has the same number of electrons in the outer shell which explains the similarities in chemical behaviour.

Question 4

periods in the periodic table share similar…..properties beacuse…..

Answer 4

chemical and physical patterns

The number of the period is the number of the highest energy electron shell of that element.

Periods often show gradual changes in properties. These patterns are repeated across each
Period. This is called periodicity.

Question 5

define

Periodicity

Answer 5

Periodicity is a regular periodic variation of properties of elements with atomic number and position in the Periodic Table.

Question 6

Periodicity in electronic configuration:

Answer 6

The periodic table can be divided into blocks showing an elements highest energy sub-shell

Question 7

define

ionisation energy

Answer 7

First ionisation energy is the energy required to remove 1 electron from each atom in
one mole of gaseous atoms of an element to form one mole of gaseous 1+ ions.

AN ATOM HAS AS MANY IONISATION ENERGIES AS IT HAS ELECTRONS

(In short, the energy required to remove 1 mole of electrons from 1 mole of gaseous
atoms to form one mole of gaseous 1+ ions)

Question 8

First ionisation energy can be represented using an equation…

Answer 8

Na (g) –>Na+ (g) + e-

Question 9

define

Second ionisation energy

Answer 9

Second ionisation energy is the energy required to remove 1 electron from each
1+ ion in one mole of gaseous ions of an element to form one mole of gaseous 2+ ions.

Question 10

Factors affecting ionisation energy:

Answer 10

• atomic radius
• nuclear charge
• electron sheilding

Question 11

whats the impact of an increasing

atomic radius on ionisation energy

Answer 11

IE decreases

the GREATER the distance between the nucleus and the outer electrons, the WEAKER the
nuclear attraction. Atomic radius has a large effect.

Question 12

whats the impact of an increasing

nuclear charge on ionisation energy

Answer 12

IE increases
the MORE PROTONS contained in
the nucleus the GREATER the nuclear attraction.

Question 13

whats the impact of an increasing

Electron shielding on ionisation energy

Answer 13

IE decreaes
negatively charged electrons that
are on the inner-shells cause repulsion with the
outer shell electrons – this is known as the shielding
effect. This REDUCES the attraction between the
nucleus and the outer shell electrons

Question 14

Periodicity of what 4 properties

Answer 14

• electron configuration
• ionisation energy
• stucture
• melting point

Question 15

the second ionisation energy produces a …. ion from a …. ion

Answer 15

2+ ion from a 1+ ion

Question 16

ionisation energy and affinity

Answer 16

Ionization energy is the amount of energy it takes to remove an electron from an atom. Electron affinity is how much energy that is released when an atom gains an electron. They are in direct relation to each other, so atoms with high ionization energy will also have high electron affinity.

Question 17

statethe trend in 1st ionisation energy

down a group

Answer 17

• atomic radius increaes
• more inner shells so sheilding increaes
• nuclear attraction on outer electrons decreaes
• first ionisation energy decreases

Question 18

trend in 1st ionisation energy

across a period

Answer 18

• nuclear charge increases (more protons)
• Same shell no. similr sheilding
• nuclear attraction increases
• atomic radius decreases
• first ionisation energy increases

Question 19

,exception to general trend

why is Berylium higher than boron?

if in doubt draw out

Answer 19

the outer electron in boron is in the 2p subshell wich is higher energy than 2s so further from the nucleus so has additional sheilding

Question 20

,exception to general trend

why is oxygen lower than nitrogen?

if in doubt draw

Answer 20

the 2p subshell in oxygen has a paired electron orbital wich repel one another hense is easier to remove (nitrogen hace equal repulsion)

Question 21

which three elments express giant covalent structure?

Answer 21

• B
• C
• Si