C1.2 Atomic structure

Question 1

what is an atom?

Answer 1

the smallest particle of an element that still has its chemical properties - diff elements made from diff atoms

Question 2

what is a molecule?

Answer 2

made from 2 or more atoms joined together - joined by chemical bonds

Question 3

radius of an atom

Answer 3

approx 10^-10m

Question 4

what subatomic particles is the nucleus of an atom made from?

Answer 4

protons and neutrons

Question 5

proton - relative mass, relative charge

Answer 5

1, +1

Question 6

neutron - relative mass, relative charge

Answer 6

1, 0

Question 7

electron - relative mass, relative charge

Answer 7

0.0005, -1

Question 8

what is the atomic number?

Answer 8

the number of protons in its nucleus

Question 9

what is mass number?

Answer 9

the total number of protons and neutrons

Question 10

what is an isotope?

Answer 10

atoms (of the same element) with same number of protons and electrons but diff numbers of neutrons. TMT same atomic number but diff mass number. Have identical chemical properties but diff physical properties

Question 11

what is an ion?

Answer 11

a charged particle

Question 12

how are ions formed?

Answer 12

when atoms, or groups of atoms, lose or gain electrons - e.g. during a chemical reaction

Question 13

what did John Dalton suggest?

Answer 13

that all matter is made from atoms, diff elements have diff atoms, all atoms of an element are identical

Question 14

what did John Dalton believe an atom looked like?

Answer 14

a tiny solid ball - technology of his time didn’t let him investigate in enough detail

Question 15

what id J.J. Thompson discover?

Answer 15

the electron

Question 16

observation of J.J. Thompsons plum pudding model

Answer 16

• atoms contain electrons
• atoms are neutral overall
• atoms are spheres of + charge with electrons dotted around inside

Question 17

what did Ernest Rutherford do?

Answer 17

pointed beams of positively charged particles, called alpha particles at thin gold foil - some particles went straight through, some slightly changed direction, some bounced back.

Question 18

what did Ernest Rutherford suggest?

Answer 18

an atom has a positively charged nucleus, containing most of its mass and outside the nucleus, electrons orbit like planets in a solar system

Question 19

what did Neils Bohr do?

Answer 19

realised orbiting electrons would be attracted to positive nucleus and would rapidly spiral inwards. Bohr showed electrons occupy fixed energy levels, or shells, around the nucleus

Question 20

what are molecules?

Answer 20

made up of 2 or more atoms