Deck 2

Question 1

Hydrated

Answer 1

Hydrated for the crystalline form that contains water molecules.

Question 2

Anhydrous

Answer 2

Anhydrous for the form without water

Question 3

What is the dot formula for the following empirical formula: MgCL2H10O5?

Answer 3

MgCl2*5H2O

Question 4

What might trip you up when converting from the empirical formula to dot formula?

Answer 4

The oxygens in the empirical formula do not all belong to the H2O, it might be part of a salt.
- Always work out the number of water molecules per salt through looking at the number of hydrogen atoms.

Question 5

What is the problem sometimes with heating a hydrated salt to form an anhydrous salt?

Answer 5

The heat could decompose the actual salt.

Question 6

Oxidation number

Answer 6

An oxidation number is a measure of the number of electrons that an atom uses to bond with atoms of another element. Oxidation numbers are derived from a set of rules.

Question 7

What is the oxidation number of an uncombined element?(C,O2,P4)

Answer 7

0

Question 8

What is the oxidation number of a combined oxygen?(H2O, CaO)

Answer 8

-2

Question 9

What is the oxidation number of a combined hydrogen

?(H2O,NH3)

Answer 9

+1

Question 10

What is the oxidation number of a simple ion?(Na+, Mg2+)

Answer 10

Charge on ion.

Question 11

What is the oxidation number of a combined fluorine?(NaF,AlF3)

Answer 11

-1

Question 12

What evidence shows that electrons are in shells?

Answer 12

The ionisation energies as they show sharp jumps when an a new electron shell is reached.

Question 13

Explain how ionisation works.(Dont talk about moles or the definition).

Answer 13

To form a positive ion, energy must be supplied to an electron to overcome the attraction from the nucleus. Electrons in the outer shell are removed first since they experience the least nuclear attraction.

Question 14

Explain the relationship between atomic radius and the attraction of a nucleus to an outer shell electron.

Answer 14

The greater the atomic radius the smaller the nuclear attraction experienced by an electron.

Question 15

Explain how nuclear charge affects the nuclear attraction to an electron.

Answer 15

The greater the nuclear charge, the greater the attractive force on the outer shell electrons.

Question 16

Explain electron shielding

Answer 16

Inner shells of electrons repel outer shell electrons, this repelling effect is called electron shielding or screening, the more inner shells there are, the larger the shielding effect and the smaller the nuclear attraction experienced on the outer shell electrons.

Question 17

How many ionisations do certain elements have?

Answer 17

An element has as many ionisation energies as it has electrons.

Question 18

Why does each successive ionisation energy require more energy?

Answer 18

As each electron is removed, there is less repulsion between the electrons and each shell will be drawn slightly closer to the nucleus.

Question 19

On an ionisation energy vs electron graph, what does a sudden increase in ionisation energy signify?

Answer 19

It signifies that a new shell has been broke into, this reduces repulsion greatly and so requires more energy.

Question 20

What is an atomic orbital?

Answer 20

An atomic orbital is a region of space were up to two electrons can occupy with opposite spins.

Question 21

What are the four different types of orbitals?

Answer 21

Theres s,p,d or f.

Question 22

Explain the s-sub shells.

Answer 22

From n=1 each shell contains on s-sub shell. Each s-sub shell contains 2 electrons because each s-sub shell has one s-orbital and each orbital can hold two electrons.

Question 23

Explain p-sub shells.

Answer 23

P-orbitals have a 3-dimensional shape. From n=2 upwards, each shell contains three p-orbitals. There are 3 p-orbitals in each p-sub shell. The p-orbitals are at right angles to one another and a one p-sub shell contains 6 electrons since there are three orbitals and each orbital contains two electrons.

Question 24

Explain d-sub shells.

Answer 24

• From n=3 upwards each d-sub shell contains 5 d orbitals.
• Each orbital holds 2 electrons and there are five d orbitals so a d sub shell holds 10 electrons.
• Shape of d sub shell not required to know.

Question 25

Explain f-sub shells.

Answer 25

From n=4 upwards each shell contains seven f-orbitals. This gives a total of 7x2=14 electrons per f-sub shell.

Question 26

Explain how to draw in electron boxes.

Answer 26

• Electrons in orbitals have opposite spin and so the arrows must be drawn in opposite directions in the boxes.
• Each electron fills up one electron box in its sub-shell before its start filling the single orbitals with another electron.

Question 27

What is a sub-shell?

Answer 27

A sub-shell is a group of the same type of atomic orbitals within a shell.

Question 28

What is the weird relationship between the 4s sub shell and 3d sub shell?

Answer 28

1) Orbitals fill in energy level order, but:
- the 4s energy level is below the 3d energy level.
- the 4s-orbitals fill before the 3d-orbitals.

Question 29

How are long electron configurations for elements shortened?

Answer 29

It is often abbreviated by basing the inner shell configuration on the noble fas that comes before the element in the periodic table. This shortening allows you to concentrate on the important outer shell portion of the electron configuration.

Question 30

What is the expection to the 3d/4s rule for certain elements in the d-block?

Answer 30

The elements Sc to Zn at the top of the d-block have the 4s and 3d energy levels so close together that, after the 4s-orbital has been filled, it is actually at a slightly higher energy than the 3d level.

Question 31

Examiner tip:

Answer 31

For the top of the d-block transition elements 4s is first in; first out. But the electron configuration for it can be written with the 4s before or after the 3d sub shell.