The periodic Table

Question 1

Which elements are naturally occuring?

Answer 1

Up to and including uranium (92)

Question 2

Where do the unnaturally occuring elements be created?

Answer 2

Synthesised by chemists in nucleur reactor or synchatron.

Question 3

What are periods and groups? PG

Answer 3

In groups of elements with similar chemical and physical properties.
Periodis corresponds to the number of the outer shell of the atom.

Question 4

How is the periodic table organised? 4 main principles

Answer 4

1. Atomic number (not mass) determines order of elements.
2. Repeating patterns of electron configuration observed when arranged in order of increasing energy level
3. Arrangement of outer shell electrons is most important in determining chemical properties
4. Periodic reccurance of similar properties results from periodic change in the electronic structure.

Question 5

General patterns of metals ‘7

Answer 5

High melt b and m point
Good conductors of heat and electricity
Opaque
Shiny appearence
Ductile and malleable.
Strong
Form positive ions

Question 6

General patterns of non metals ‘7

Answer 6

Low m and b point
Poor conductors of heat and electricity
Transparent in a thin sheet
Dull
brittle
weak
form negative ions

Question 7

What are the trends in atomic radii?

Answer 7

Decreases across periodic table increases down group.

Question 8

What element has the smallest radii and how big is it?

Answer 8

0.030nm

Question 9

What is important to remember about radii?

Answer 9

DOUBLE FOR DIAMETER

Question 10

Why is this trend? atomic radii

Answer 10

Going down a group, electrons are added to successive shells which are each further from the nucleus. Also the shells close to the nucleus create a shielding effect reducing the pull of the nucleus and the outer shell electrons.
Going across the group the elements have the same number of shells but protons and electrons are added, and so there is greater attraction between them, pulling the electrons in.

Question 11

What is ionisation energy?

Answer 11

Energy required to remove an electron from an element in gaseous state (vacuum)

Question 12

What is the unit for ionisation energy?

Answer 12

Kj mol^-1

Question 13

Trends of ionisation energy?

Answer 13

Decreases going down a group

Increases as we move left to right across period

Question 14

Why is this trend? Ionisation energy

Answer 14

The shells are further away from nucleus and shielding for groups
Shelding is constant and there are more protons and electrons are held closer.

Question 15

what is electronegativity?

Answer 15

The measure of the degree to which an atom can attract an electron to itself.

Question 16

Trends for electronegativity?

Answer 16

Going across a period it increases.

Going down a group electronegativity decreases.

Question 17

Why is this trend? Electronegativity

Answer 17

Going across period, nuclear charge increases, and you get a higher electron attracting power.
Going down a group, there is shielding and the the shells are further from the nucleus

Question 18

What is mettalic characteristics?

Answer 18

an elements ease of losing electrons

Question 19

Trends? metallic characterisitics

Answer 19

Decreases across a periodic

increases down a group

Question 20

Why is this trend? Metallic charastics

Answer 20

Across period, because there is higher nuclear charge and cant make positive ions
Down group, shells are further away from nucleus and shielding so easy to lose electrons

Question 21

What is the oxidising strength of an element?

Answer 21

How readily an element gains electrons,

They are strong oxidisers because they oxidise something else and it itself becomes reduced.

Question 22

What is the reducing strength of an element?

Answer 22

How readily an element loses electrons.

They are strong reductants and are themselves oxidises.

Question 23

Why trends in oxidise and reducing?

Answer 23

going down a group elements give up electrons more easily due to shielding and distance from nucleus.
Going across period harder to give up electrons as nuclear charge increases.