C1-PARTICLES

Question 1

what is a particle

Answer 1

A tiny bit of matter

Question 2

what does the particle model describe

Answer 2

how particles are arranged and how they move in solids,liquids and gases

Question 3

solids as descibed in the particle model

Answer 3

regular arrangement
very close distance between particles
vibrate around fixed positions

Question 4

liquids as descibed in the particle model

Answer 4

random arrangement
close distance
move around eachother

Question 5

gases as descibed in the particle model

Answer 5

random arrangement
far apart
move quickly in all directions

Question 6

why can you not compress a substance that is in its solid or liquid state

Answer 6

There is no space for the particles to move into

Question 7

why can a solid not flow

Answer 7

particles vibrate around fixed positions and cannot move from place to place.

Question 8

what is a physical change

Answer 8

when a substance changes shape or state,but no new substances are made.Rversible

Question 9

examples of physical changes

Answer 9

mixing sand with water

dissolving sugar and water

Question 10

what is a chemical change

Answer 10

a change that produces a new substance.They may look or taste different,or be in a different state.Irreverisble

Question 11

example of chemical changes

Answer 11

cooking eggs
steel rusting
acid reacting with alkali to make salt and water

Question 12

what happens to particles during change

Answer 12

physical-particles stay the same but arrangement and movement change

chemical-particles break up and then join together in different ways.This is how new substances are made

Question 13

What are atoms

Answer 13

smallest part of an element that retains the properties of that same element

Question 14

size of atoms

Answer 14

radius of 1x10^-10
mass of about 10^23

Question 15

formula for ratio of distance to diameter

Answer 15

ratio of distance to diameter=distance between atoms/diameter of atoms.

Question 16

what are the forces between particles

Answer 16

electrostatic forces of attraction between positive and negative charges.

Question 17

what are the limitations of the particle model

Answer 17

-forces between the particles
-size of the particles
-space between particles

Question 18

what is a molecule

Answer 18

made from two or more atoms joined together

Question 19

what is inside an atom

Answer 19

protons- 1 +1
neutrons- 1 0
electron: 0.005 -1

Question 20

mass number =

Answer 20

protons and neutrons

Question 21

atomic number=

Answer 21

protons

Question 22

number of neutrons

Answer 22

mass number-atomic number

Question 23

what are isotopes

Answer 23

atoms with same number of protons and elctrons,but diff number of neutrons-meaning the mass number is different

Question 24

what are ions

Answer 24

charged particles

formed when atoms lose or gain electrons in chemical reactions

Question 25

Dalton in 1803

Answer 25

-solid sphere -all atoms of an element are identical -different elements contain different types of atom

Question 26

JJ Thompson in 1897

Answer 26

-discovered the electron-found that beams of cathode rays changed direction in electric and magnetic fields.Concluded that cathode rays were actually tiny particles of negative charge and smaller than atoms -atoms contained electrons -atoms are neutral overall -plum pudding model with a sphere of positive charge and electrons dotted around it

Question 27

Rutherford in 1909

Answer 27

-sent alpha particles through thin gold foil.some deflected,indiacating some negative thing was there-a positively charged nucleus -also suggetsed that outside the nuclues electrons orbit like planets in a solar system

Question 28

Bohr in 1913

Answer 28

-used mathematical models to suggest electrons occupy fixed energy levels,or shells around the nuclues as he realised orbiting electrons would be attracted to positive nucleus and spiral inwards