Perodic Table

Question 1

What is the periodic table?

Answer 1

list of all the elements in order of increasing atomic number

Question 2

What can the periodic table be used for?

Answer 2

predict the properties of an element from its position in the table

explain the similarities of certain elements and the trends in their properties by electronic configuration

Question 3

What does it mean if elements touch the red line on the periodic table?

Answer 3

Elements that touch this line, such as silicon, have a combination of metallic and non-metallic properties. Known as semi-metals

Question 4

How is the periodic table divided in terms of blocks?

Answer 4

S-block, P-block, D-block and F-block

All the elements that have their highest energy electrons in s-orbitals are in the s-block

All the elements that have their highest energy electrons in p-orbitals are called p-block,

All the elements that have their highest energy electrons in d-orbitals are called d-block

Question 5

Why is Scandium and Zinc not considered as transition metals?

Answer 5

Scandium and zinc are not transition metals because they do not form any compounds in which they have partly filled d-orbitals

Question 6

Why is light emitted in a chemical reaction?

Answer 6

When elements are heated they give out light energy at certain wavelengths, as excited electrons fall back from one energy level to a lower one

Question 7

How does reactivity change in the periodic table?

Answer 7

Lanthanides - tend to form +3 ions in their compounds and have broadly similar reactivity

Actinides - Radioactive metals

Transitional metals - unreactive metals

S-block > elements (metals) get more reactive going down a group
> To the right (non-metals), elements tend 10 get more reactive going up a group.

Question 8

What is the periodicity like in Group 4?

Answer 8

four electrons in its outer shell with which it forms four covalent bonds.

The element has some metallic properties and is classed as a semi-metal.

Question 9

Why does first ionisation energy increases across a period?

Answer 9

As you go across a period from left to right, the number of protons in the nucleus increases but the electrons enter the same main level. The increased charge on the nucleus means that it gets increasingly difficult to remove an electron.

Question 10

Why does first ionisation energy decreases going down the group?

Answer 10

The number of filled inner levels increases down the group. This results in an increase in shielding. Also, the electron to be removed is at an increasing distance from the nucleus and is therefore held less strongly.

Thus the outer electrons get easier to remove going down a group because they are further away from the nucleus.

Question 11

Why there is a drop in ionisation energy from one period to the next?

Answer 11

In the periods there is a change in electronic configuration.

This is because at the next element in the next period a new main level starts and so there is an increase in atomic radius, the outer electron is further from the nucleus, less strongly attracted and easier to remove.

Question 12

Why the radii of atoms increase down a group?

Answer 12

This is because as the atoms of each clement have one extra complete main level of electrons compared with the one before

So going down the group, the outer electron main level is further from the nucleus and the atomic radii increase. I’m

Question 13

What is first ionisation energy?

Answer 13

is the energy required to convert a mole of isolated gaseous atoms into a mole of singly positively charged gaseous ions - to remove one electron

Question 14

What happens to first ionisation energy as you go across the period?

Answer 14

The first ionisation energy generally increases across a period-alkali metals (e.g.sodium) have the lowest values and the noble gases (e.g.helium)

Question 15

What happens to first ionisation energy as you go down the group?

Answer 15

decreases going down any group

Question 16

What is the trend in atomic radii in the periodic table?

Answer 16

Atomic radius is a periodic property because it decreases across each period and there is a jump when starting the next period

Atoms get larger down any group.

Question 17

What is the physical and chemical trend as you go across a period?

Answer 17

trends in physical properties and chemical behaviour as you go across a period

Question 18

Why is there a drop in first ionisation energy between Groups 2 and 3?

Answer 18

For the first ionisation energy:

• Magnesium loses a 3s electon
• Aluminium loses a 3p electron.

The p-elenron is already in a higher energy level than the s-electron, so it takes less energy to remove it.

Question 19

Why is there a drop in first ionisation energy between Groups 5 and 6?

Answer 19

An electron in a pair will be easier to remove that one in an orbital on its own because it is already being repelled by the other electron