C1 Atomic Structure

Question 1

What is an atom?

Answer 1

Very small particles which can only be seen with special microscopes. Everything is made of atoms

Question 2

What is an element?

Answer 2

Substances made of one type of atom

Question 3

How are elements represented with symbols?

Answer 3

The first letter is always capital and it can be one or two letter. The word of the symbol usually origins from the Latin word

Question 4

What is a compound?

Answer 4

Atoms of at least two different types bonded together. They require a chemical reaction to be broken up

Question 5

What happens to atoms in a reaction?

Answer 5

The number and type of atoms are still the same, they have just been rearranged to make new compounds

Question 6

How do you know if an equation is balance?

Answer 6

If there is the same number of each atom in the reactants and products

Question 7

Law of conservation of mass

Answer 7

Mass is never gained or loss in a chemical reaction

Question 8

What happens to the atoms in a chemical reaction?

Answer 8

Rearranged into different compounds. No new atoms are created and no atoms disappear

Question 9

What is a Independent Variable?

Answer 9

Cause, controlled - the one thing you change

Question 10

What is a Dependent Variable?

Answer 10

Effect - Depends on the independent variable

Question 11

What is a Control Variable?

Answer 11

What remains constant and unchanging

Question 12

What is a mixture?

Answer 12

Groups of atoms, elements, and compounds that are mixed but not bonded

Question 13

What is filtration?

Answer 13

To separate an insoluble solid from a liquid. E.g. sand and water

Question 14

What is crystallisation ?

Answer 14

Used to purify substances. Often when a solid substance is placed into a liquid, it dissolves. The way to separate the soluble solid is to evaporate off the solvent

Question 15

Solute

Answer 15

A solid that can dissolve in a solvent

Question 16

Solvent

Answer 16

A substance that dissolves a solute

Question 17

Solution

Answer 17

Mixture formed when a solute dissolves in a solvent

Question 18

What is simple distillation?

Answer 18

Used to separate a liquid from a solution. The liquid evaporates from solution, then it cools and condenses. This works due to the different boiling points of liquids.

Question 19

Why is it difficult for simple distillation to separate pure liquids from mixtures of similar boiling points?

Answer 19

A vapour is given off from each liquid before the actual boiling point, so the liquids might not be completely pure

Question 20

What is fractional distillation for?

Answer 20

Separate miscible liquids (liquids that mix) that have different boiling points. E.g. making whisky and vodka, separating petrol from crude oil…

Question 21

How does fractioning column work?

Answer 21

Temperature is highest at the bottom. A substance with a high boiling point will condense at the bottom. A substance with a lower boiling point will rise through the column towards the top

Question 22

Soluble

Answer 22

It will dissolve

Question 23

Solubility

Answer 23

A measure of how much a substance dissolves

Question 24

Saturated

Answer 24

No more will and can dissolve

Question 25

What is chromatography for?

Answer 25

Testing water samples, detect drugs, detect pesticides, forensics, detect additives

Question 26

How does chromatography work?

Answer 26

Separate mixture according to the size of their particles. As the solvent rises through the paper, it dissolves the sample mixture, which then travel up the paper. Small particle travel further than large particles, due to the difference in solubility and their attractions with the paper

Question 27

John Dalton 1766-1844 Atoms

Answer 27

Published his ideas about atoms in 1803. - Thought that all matter was made of tiny particles called atoms - Imagined as tiny spheres that could not be divided. It was only a theory

Question 28

J.J. Thomson 1856-1940

Answer 28

Discovered the electron in 1897. Proposed a sphere of positively charge with negatively charged electrons spread through it The Plum Pudding model

Question 29

Ernest Rutherford 1871-1937

Answer 29

Carried out experiments in Manchester in 1909 - Fired alpha particles at a piece of thin gold foil - Alpha particles are positively charged Conclusion that the atom is made up of a small central nucleus surrounded by electrons Called the nuclear model which replaced the plum pudding model

Question 30

Rutherford's conclusions

Answer 30

Most alpha particles go straight through -> Most of the atom is empty space Some alpha particles were deflected and few were reflected -> Small, positively charged nucleus in the centre of the atom

Question 31

Niels Bohr 1885-1962

Answer 31

Adapted the nuclear model in 1913 - Electrons orbit the nucleus at specific distances - Now called the electron shells

Question 32

James Chadwick 1891-1971

Answer 32

Discovered the neutron in 1932 - Provided the evidence to show the existence of neutrons within the nucleus - Explains where the added mass came from (already had evidence of protons)

Question 33

Whag does the atomic number show?

Answer 33

Number of protons It is the smaller number on the periodic table for each atom

Question 34

Number of electrons

Answer 34

Equal to the number of protons if the atom has a neutral charge

Question 35

Number of neutrons

Answer 35

Mass number - Atomic number

Question 36

Mass number

Answer 36

Number of electrons + number of protons

Question 37

Electronic Configuration

Answer 37

1st shell holds a maximum of 2 electrons. 2nd and 3rd shell holds a maximum of 8 electrons

Question 38

What makes an element?

Answer 38

Defined by the number of protons. If the number of protons changes, it is a different element.

Question 39

What happens when there is a different number of electrons?

Answer 39

It will stay the same element if the number of protons doesn't change. However, electrons have a negative charge, so if an electron is taken away, it will become a positive ion and if an electron is given, the atom will become a negative ion (balanced protons and electrons make the atom neutral)

Question 40

What is an ion?

Answer 40

Gaining or losing an electron turns an atom into an ion - Gaining turns it into a negative ion (more electrons than protons) - Losing turns it into a positive ion (more protons than electrons)

Question 41

What happens when the number of neutrons changes?

Answer 41

- Neutrons do not have a charge so the charge of the atom will remain. - Neutrons have a mass of 1 so the mass of the atom will change - Number of protons stays the same so it will be the same atom but with a different mass number This is called an Isotope

Question 42

What is an isotope?

Answer 42

- Have the same chemical properties because it is still the same type of atom - Mass changes so physical properties can change. E.g. boiling point. - Each element can have different isotopes. Mass number in the periodic table represents the average mass of the different isotopes