Atoms, elements and compounds

Question 1

Some not metal elements exist as molecules, name them.

Answer 1

Iodine, Bromine, Chlorine, Fluorine, Oxygen, Nitrogen and Hydrogen

Question 2

What is a compound?

Answer 2

two or more elements that are chemically combined

Question 3

What is an Ion?

Answer 3

An ion is a charged particle formed when an atom, or a group of atoms, loses or gains electrons.

Question 4

What is a reactant?

Answer 4

Reactants are substances that react together in a chemical reaction.

Question 5

How do word equations take form?

Answer 5

reactants → products

Question 6

Word equation for Sodium Chloride?

Answer 6

sodium + chlorine → sodium chloride

Question 7

What is a balanced chemical equation?

Answer 7

A balanced chemical equation = a chemical reaction using the formulae of the reactants and products. Shows the number of units of each substance involved.

Question 8

What’s a pure mixture?

Answer 8

Substance that consists of one element/compound

Question 9

What’s a mixture?

Answer 9

a mixture consists of two or more different substances, not chemically joined together

Question 10

What’s Filtration?

Answer 10

Filtration is used to separate an insoluble solid from a liquid

Question 11

What is Cyrstallisation?

Answer 11

Crystallisation is used to produce solid crystals from a solution. It is heated until crystals remain.

Question 12

What’s simple distillation?

Answer 12

Simple distillation is used to separate a solvent from a solution. Work by going to one liquids boiling point but not the others.

Question 13

What’s Fractional distillation?

Answer 13

Fractional distillation is used to separate different liquids from a mixture of liquids. It’s used to separate several liquids based on their boiling points.

Question 14

What’s Chromatography?

Answer 14

Paper chromatography is used to separate mixtures of soluble substances

Question 15

What did John Dalton think? (1803)

Answer 15

He thought that all matter was made of tiny particles called atoms, which he imagined as tiny spheres that could not be divided.

Question 16

What did JJ Thomson think? (1900’s)

Answer 16

He discovered the electron and the plum pudding model. In this model, the atom is a ball of positive charge with negative electrons embedded in it.

Question 17

What did Ernest Rutherford think? (1909)

Answer 17

He designed an experiment to test the plum pudding model. Positively charged alpha particles fired at gold foil. Most alpha particles went straight through foil but some scattered, this led Rutherford to suggest new model (Nuclear Model.)

Question 18

What did Niels Bohr think?

Answer 18

Bohr did calculations that led him to suggest electrons orbit the nucleus in shells. The shells are at certain distances from the nucleus. Further experiments led to the idea that the nucleus contained small particles, protons. Each proton has a small amount of positive charge.

Question 19

What did James Chadwick think?

Answer 19

He found evidence for the existence of particles in the nucleus with mass but no charge. These particles are called neutrons. This led to another development of the atomic model, which is still used today.

Question 20

What is an atomic number?

Answer 20

The number of protons.

Question 21

What’s an isotope?

Answer 21

When an element has the same atomic number but a different mass number.