C1 Atomic Structure.

Question 1

Define an atom.

Answer 1

The smallest part of an element that can still be recognised as that element.

Question 2

Define an element.

Answer 2

A substance made of only one type of atom.

Question 3

Define a compound

Answer 3

A substance made of two or more different atoms chemically bonded together.

Question 4

Define a molecule

Answer 4

A substance made of more than one atom chemically bonded together (it can be atoms of the same type).

Question 5

Define a mixture.

Answer 5

A substance made of more than one substance not chemically bonded together.

Question 6

State the three subatomic particles.

Answer 6

Protons, neutrons and electrons.

Question 7

State the masses of the subatomic particles.

Answer 7

Protons: 1
Neutrons: 1
Electrons: Virtually no mass.

Question 8

What is the plum pudding model of the atom?

Answer 8

A ball of positive charge with negative electrons studded into it.

Question 9

What did Rutherford’s alpha scattering experiment prove?

Answer 9

Atoms have a small dense nucleus with a positive charge.

Question 10

What is the radius of the atom?

Answer 10

0.1 nanometers.

1 x 10^-9 m

Question 11

Define the separation method of crystallisation and describe how it is carried out.

Answer 11

• Crystallisation separates solutions into their different parts: dissolved solids (solutes) and liquids (solvents).
• Crystallisation is performed by heating the mixture so that the solvent evaporates.
  - Eventually, crystals of the solute (dissolved solids) will form.
  - We can collect the solvent (liquid) by condensing it as it evaporates.

Question 12

Define the separation method of filtration and describe how it is carried out.

Answer 12

• Filtration separates mixtures that contain insoluble (can’t dissolve) solids and liquids (which are soluble).
• Filtration is performed by pouring the mixture through filter paper:
  - The insoluble solid is trapped by the filter paper.
  - The liquid runs through the filter paper and is collected below.

Question 13

Define the separation method of chromatography and describe how it is carried out.

Answer 13

• Chromatography separates solutions with a number of different solutes (solids) in the solvent (liquid).
• Place a drop of the solution to be separated near the bottom of a piece of chromatography paper. Dip the very bottom of the paper into a suitable solvent. The solvent (liquid) moves up the paper and carries the solutes (solids) in the solution with it.
• Different solutes (solids) move at different speeds, so they separate on the paper.

Question 14

Give 5 factors of the nucleus of an atom.

Answer 14

1) It’s in the center of the atom
2) It contains protons and neutrons
3) The nucleus has a radius of around 1 x 10^-14
4) It has a positive charge because of the protons
5) Almost the whole mass of the atom is concentrated in the nucleus.

Question 15

Give 4 factors of electrons

Answer 15

• They move around the nucleus in electron shells.
• They are negatively charged and very small
• The volume of their orbits determines the size of the atom
• Electrons have virtually no mass.

Question 16

What is an ion?

Answer 16

• An ion is an atom of group of atoms that has lost or gained electrons.

Question 17

In an element what do all the atoms have in common.

Answer 17

• The number of protons.

Question 18

What is an isotope?

Answer 18

• An isotope is a different form of the same element which have the same number of protons but a different number of neutrons.

Question 19

What is the formula to figure out the relative atomic mass Ar of an element?

Answer 19

Sum of (isotope abundance x isotope mass number) / sum of abundances of all the isotopes