Chemistry

Question 1

Define- chemical change

Answer 1

When a new substance forms during a chemical reactions and cannot be easily reversed.

Question 2

Define- physical change

Answer 2

A change of state, between solid, liquid and gas and no new substance is formed (can be easily reversed)

Question 3

Define- atom

Answer 3

Smallest particle of an element

Question 4

Define- periodic table

Answer 4

Table is which all of the known elements are arranged

Question 5

Define- atomic number

Answer 5

Number of protons/electrons in an atom

Question 6

Define- malleable

Answer 6

Property of a metal- can be shaped

Question 7

Define- density

Answer 7

The mass of a substance divided by it’s volume to determine how close the particles inside are

Question 8

What is density measured in?

Answer 8

g/cm3 or kg/L

Question 9

Define- conductor

Answer 9

Property of a metal that can let electricity and heat through it easily

Question 10

Define- mass number

Answer 10

Number of protons plus neutrons in the nucleus of an atom

Question 11

Define- proton

Answer 11

The positively charged particle found in the nucleus of the atom

Question 12

Define- neutron

Answer 12

The neutral particle found in the nucleus of an atom

Question 13

Define- electron

Answer 13

The negatively charged particle, with no mass, found in the orbitals surrounding the nucleus.

Question 14

Define- ion

Answer 14

An atom or molecule that has gained or lost electrons to form a full valence shell and become stable.

Question 15

Define- reactant

Answer 15

A substance that takes part in, or gets changed in a chemical reaction. Appears on the left in a word or symbol equation)

Question 16

Define- product

Answer 16

The substances that form during a chemical reaction (appears on the right in a word or symbol equation)

Question 17

Define- valence shell

Answer 17

The outermost orbital of an atom

Question 18

Distinguish between where metals and non-metals are located on the periodic table

Answer 18

The nonmetals are located on the upper right side of the periodic table. The metals are located on the left side.

Question 19

What properties do all metals share?

Answer 19

Lustrous, malleable, ductile and electrical conductors

Question 20

What are the columns called?

Answer 20

Groups

Question 21

What are the rows called?

Answer 21

Periods

Question 22

What do atoms in the same GROUP have?

Answer 22

The same number of valence electrons

Question 23

What do atoms in the same PERIOD have?

Answer 23

The same number of electron shells

Question 24

Why are atoms in group 18 called noble gases?

Answer 24

They have full valence shells so can’t form ions or compounds

Question 25

What does the electron arrangement show?

Answer 25

The electron arrangement shows how many electrons are on each shell

Question 26

Why are atoms neutral overall?

Answer 26

Atoms are neutral overall because the total number of negatively charged electrons is the same as the number of positively charged protons so they cancel each other out

Question 27

What do word equations show?

Answer 27

Word equations show what has happened in a reaction

Question 28

What happens if an atom loses electrons?

Answer 28

It forms a positive charged ion

Question 29

What happens if an atom gains electrons?

Answer 29

It forms a negative charged ion

Question 30

Why are ionic compounds neutral overall?

Answer 30

The positive and negative charges of the ions cancel each other out

Question 31

What are some observations you would see during a chemical reaction?

Answer 31

Colour change, fizzing/bubbles meaning gas is being produced, heat or light is produced, burning anything (a reaction to oxygen)

Question 32

What are some observations you would see during a physical reaction?

Answer 32

A change of shape, a change of state, dissolving

Question 33

Compare and contrast a physical/chemical change

Answer 33

A physical change is easy to reverse whereas chemical reactions are not. Physical changes can include a change of state or shape while chemical changes can include a change of colour. In both chemical and physical changes, the atoms/elements will stay the same, and a change of density could happen.