Science 2 revison

Question 1

what are nonmetals and metalloids are considered as

Answer 1

covalent

Question 2

methane symbol

Answer 2

CH4

Question 3

water symbol

Answer 3

H20

Question 4

ammonia symbol

Answer 4

NH3

Question 5

glucose

Answer 5

C6H1206

Question 6

To get the atomic mass you must…

Answer 6

protons + neutrons

Question 7

13-20 periodic elements

Answer 7

Aluminium, Silicon, phosphorous, Sulphur, chlorine, argon, potassium, calcium

Question 8

what are metals

Answer 8

• solid at room temp
• shiny except for mercury which is a liquid
• malleable
• melt at high temp
• ductile
• conductors of electricity and heat

Question 9

what are non-metals

Answer 9

poor conductors of electricity
- brittle
- melt at low temp
- dull
11 are gasses
10 are solid
1 is liquid

Question 10

what are metalloids

Answer 10

elements that have features of both metal and non-metal ex: silicon poor conductor of heat and electricity but is polished
there are 8 altogether in table

Question 11

where can elements be found in different arrangements

Answer 11

• single atoms called monatomic substances
• chemically bonded atoms called molecules
• large dimensional grids called lattices

Question 12

what is a molecule?

Answer 12

A molecule is a group 2 or more non-metal atoms bonded (or joined) together. Molecules can also be an element if they are only one type of atom e.g. O2 but they are a compound if they consist of more than one type of non-metal atom e.g. H2O

Question 13

What are physical changes

Answer 13

• Can involve changes of state such as:
  ○ Solids melting into liquids
  ○ Liquids freezing or solidifying into solids
  ○ Liquids vaporising into gases
  ○ Solids dissolving into solutions
  
  • A new substance is not formed
  • Are easier to reverse

Question 13

what are compounds

Answer 13

A compound consists of atoms of two or more different elements bound together. Compounds that consist of non-metals bonded to metals are called ionic compounds e.g NaCl (sodium chloride or table salt)

Question 14

what are chemical changes

Answer 14

• Can involve:
  ○ Colour change
  ○ Heat and light being produced
  ○ Bubbling
  ○ A precipitate forming
  
  • A new substance is formed
  • Are difficult to reverse

Question 15

Definition of physical change

Answer 15

is a change that affects one or more properties of a substance but does not change its chemical composition

Question 16

definition of chemical change

Answer 16

a change that results in a new formation of a chemical substance

Question 17

precipitate forms

Answer 17

when a solid suddenly appears in a solution and settles to the bottom
ex: milk going off gets chunky

Question 18

gas forms

Answer 18

when gases produced in a chemical reaction are released ex: bubbles in soda

Question 19

Energy changes in reactions

Answer 19

when a chemical change reaction happens, energy is transferred between the reaction mixture and its surroundings

Question 20

Describe how substances are composed of atoms.

Answer 20

Substances are made up of atoms, which are the basic building blocks of matter. An atom consists of three primary particles: protons, neutrons, and electrons.

Question 21

Summarise the development of the atomic model.

Answer 21

Greek philosophers
Dalton
Thompson
Rutherford
Bohr
Chadwick

Question 22

Describe the structure of a lattice

Answer 22

A lattice is a large dimensional grid to show the arrangements of atoms as a solid