C1(Atomic Structure)

Question 1

What are elements,mixtures and compounds

Answer 1

-Elements contain only one type of atom
-Compounds contain more than one type of atom
-Mixture is made up of two or more substances that are not chemically combined

Question 2

What is the law of conservation of mass

Answer 2

The total mass of the products formed in a reaction is equal to the total mass of the reactants

Question 3

How can mixtures be separated

Answer 3

They can separated By physical means such as filtration, crystallisation,simple distillation, fractional distillation and chromatography

Question 4

What is filtration

Answer 4

Used to separate an undissolved solid from a mixture of the solid and the solution

Question 5

What is crystallisation

Answer 5

the process of forming solid crystals from a solution by allowing the solvent to evaporate slowly

Question 6

What is simple distillation

Answer 6

In simple distillation, a solution is heated and boiled to evaporate the solvent, the vapour given off then enters a condenser, here the hot vapour is cooled and condensed back into a liquid

Question 7

What is fractional distillation

Answer 7

Used to separate miscible liquids, using a fractionating column and the different boiling points of the liquid in the mixture

Question 8

What is paper chromatography

Answer 8

-Separates mixtures of substances dissolved in a solvent as they move up a chromatography paper
-The different substances are separated because of their solubilities in the solvent used

Question 9

What was the early ideas about atoms

Answer 9

John Dalton published his ideas about atoms in 1803. He thought that all matter was made of tiny particles called atoms, which he imagined as tiny spheres that could not be divided

Question 10

What was the evidence for electrons in atoms

Answer 10

J J Thomson carried out experiments and discovered the electron. This led him to suggest the plum pudding model of the atom. In this model, the atom is a ball of positive charge with negative electrons embedded in it

Question 11

What was the evidence for the nucleus

Answer 11

In 1909 Ernest Rutherford designed an experiment to test the plum pudding model. In the experiment, positively charged alpha particles were fired at thin gold foil. Most alpha particles went straight through the foil. But a few were scattered in different directions.

Question 12

What was the evidence for electrons in shells

Answer 12

In 1914 Niels Bohr calculations that led him to suggest that electrons orbit the nucleus in shells. The shells are at certain distances from the nucleus.

Question 13

What is the evidence for neutrons in nucleus

Answer 13

In 1932 James Chadwick found evidence for the existence of particles in the nucleus with mass but no charge. These particles are called neutrons.

Question 14

What are Atoms made of

Answer 14

Protons
Neutrons
Electrons

Question 15

What is the relative charge and mass of sub atomic particles

Answer 15

Question 16

What is the Atomic number

Answer 16

The number of electrons and protons in an element

Question 17

What is the mass number

Answer 17

The number of protons and neutrons in an atom

Question 18

How to work out number of neutrons in an atom

Answer 18

Number of neutrons= mass number- atomic number

Question 19

What are ions

Answer 19

Atoms that gain or lose electrons
Therefore giving the atom a negative or positive charge

Question 20

What are isotopes

Answer 20

Atoms of the same element with the same number of protons and electrons but with a different number of neutrons in the nucleus

Question 21

How are electrons arranged in atoms

Answer 21

Energy levels or shells
-the lowest energy level(shell 1) can hold 2 electrons
-the next energy levels( shell 2,3,4…) can hold 8 electrons
-the number of electrons in the outermost shell of an element’s atoms determine the way in which that element reacts

Question 22

Answer 22