Unit 1 - Atomic Structure and the Periodic Table

Question 1

What is the radius of an atom?

Answer 1

0.1 nanometres (1x10^-10).

Question 2

What is the radius of the nucleus?

Answer 2

1 x 10^-14m (1/10000 of the radius of the atom).

Question 3

Do electrons have any mass?

Answer 3

No.

Question 4

Which number is the atomic number? What does it tell you?

Answer 4

The bottom number. How many protons there are.

Question 5

Which number is the mass number? What does it tell you?

Answer 5

The top number. The total number of protons add neutrons.

Question 6

What is an element?

Answer 6

A substance made up of atoms that all have the same number of protons in their nucleus.

Question 7

How many elements are there?

Answer 7

About 100.

Question 8

What are isotopes?

Answer 8

Different forms of the same element, which have the same number of protons but a different number of neutrons.

Question 9

What else can the mass number be referred to as?

Answer 9

Relative atomic mass (Ar).

Question 10

How do you work out the relative atomic mass of an element?

Answer 10

Ar = sum of (isotope abundance x isotope mass number) / sum of abundances of all the isotopes.

Question 11

Explain the history of the atom.

Answer 11

John Dalton - the beginning of the 19th century, atoms as solid spheres which made up different elements.
JJ Thomson - 1897 ‘plum pudding model’ discovered electrons.
Ernst Rutherford - 1909 alpha particle scattering experiments. Fired positively charged alpha particles at a thin sheet of gold. Some went through, some deflected, some backwards. Came up with the nuclear model as it meant that concentrated tiny positive charge in the centre where most mass is concentrated if fired directly at nucleus they would deflect back. Negative electrons surround this so most of the atom is empty space. Discovered protons.
Neils Bohr - electrons orbit in fixed shells.
James Chadwick - neutrons

Question 12

What order is the periodic table?

Answer 12

Atomic mass but also takes into account chemical properties.

Question 13

What do the groups tell you? Periods?

Answer 13

The number of protons in the outer shell so they all react similarly. The number of shells.

Question 14

Give some properties of metals.

Answer 14

Strong, malleable, good conductors, high m and b points.

Question 15

Give some properties of transition metals.

Answer 15

Coloured compounds, good catalysts, can have more than one ion, good conductors, dense, strong, shiny.

Question 16

What are group 1 elements known as? Give some properties. What happens as you go down the group?

Answer 16

Alkali metals. Soft, low density, very reactive, lower melting points than transition metals. Increase reactivity, lower m and b points, higher relative atomic mass, amount of energy given out by the reaction increases.

Question 17

Generally, what are ionic substances?

Answer 17

White solids that dissolve in water to form colourless solutions.

Question 18

What are group 7 elements known as? What happens as you go down the group?

Answer 18

Halogens. Less reactive, higher melting and boiling points, higher relative atomic masses.

Question 19

What are the group 0 elements known as? Give some properties. What happens as you go down the group.

Answer 19

Noble gases. Not very reactive, inert, monatomic gases, colourless gases at room temp, non-flammable. Boiling points increases as greater intermolecular forces, relative atomic mass increases.

Question 20

How do you separate different dyes in an ink, insoluble solids from liquids, soluble solids from solutions, rock salt, solutions and a mixture of liquids?

Answer 20

Chromatography, filtration, evaporation or crystallisation, filtration and crystallisation, simple distillation, fractional distillation.