Test 1

Question 1

Chadwick

Answer 1

Discovered neutrons

Question 2

John Dalton

Answer 2

Cannot destroy atom
Distinct masses and properties

Question 3

JJ. Thompson

Answer 3

Proposed the convept of electrons

Question 4

Rutherford

Answer 4

Stated atoms consist of a positively charged nucleus (it is dense and contains all the mass)

Question 5

Niels Bohr

Answer 5

Proposed that atoms are restricted to a circular orbit

Question 6

Schrodinger

Answer 6

Proposed that electrons are found in clouds (orbitals)

Question 7

Description of metals

Answer 7

Grey solid

Question 8

Description of mercury

Answer 8

grey liquid

Question 9

Description of gold

Answer 9

Yellow solid

Question 10

Description of copper

Answer 10

Salmon pink solid

Question 11

Isotopes

Answer 11

Atoms of the same element with same number of protons but different number of neutrons

Question 12

Similarities and Differences of isotopes

Answer 12

Similarities: Same number of protons, same chemical properties (reactivity, heat conduction, stability)
Differences: Number of neutrons, different physical properties (BP/MP/Density/Radioactivity)

Question 13

Orbital

Answer 13

Region around the nucleus of an atom that can hold up to 2 electrons with opposite spins

Question 14

Element

Answer 14

Simplest kind of substance that cannot be broken down into anything simpler

Question 15

Compounds

Answer 15

Substances made of 2 or more different elements chemically bonded together

Question 16

Molecule

Answer 16

Particle containing 2 or more different elements chemically bonded together

Question 17

Atom

Answer 17

Smallest particle of element that can exist on its own

Question 18

Ion

Answer 18

atom/atoms with a positive or negative charge from gaining or losing electrons

Question 19

Empirical Formula

Answer 19

Simplest whole number ratio of a compound/element

Question 20

Electronegativity

Answer 20

The ability of an atom to attract bonding pair of electrons

Question 21

Limitations of flame test

Answer 21

• Multiple elements exhibit similar colours
• Colour assessment is subjective between individuals
• Emitted phons may lie outside visible light spectrum

Question 22

AES

Answer 22

Qualitative atomic analysis to identify the identity of a metal ion

Question 23

AAS

Answer 23

Quantitative and qualitative atomic analysis to identify the concentration of known metal ions

Question 24

Relative atomic mass

Answer 24

Mass of an atom compared to the mass of 1/12 of a carbon 12 atom

Question 25

Mass Number

Answer 25

The sum of protons + Neutrons

Question 26

How to mass spectrometry help calculate the isotopic composition of an element

Answer 26

Sample of element is taken and vapourised using a heater/laser.

An electron gun is then used to knock electrons out of the atom to form positively charged ion.

Using electrostatic plates, the ions are then accelerated.

An electromagnet is then used to deflect these ions. Heavier particles deflect less, and lighter particles deflect more.

Ions are collected and the current is measured by the detection plate, to give the number of ions of each mass to charge ratio.

The electromagnet intensity is adjusted to find the abundance of different isotopes.

Question 27

Flame test

Answer 27

Qualitative analysis to identify the identity of a metal ion

Question 28

Energy levels

Answer 28

Electrons exist in different principle quantum levels e.g. (n=1, n=2, n=3). The cannot exist between principle quantum levels

Question 29

How are flames tests used to identify elements

Answer 29

Electrons can be excited by heat. A salt is mixed with ethanol, and the ethanol is lit by a match. The heat from the flame excites the electrons of the metal ions in the salt. These electrons jump principle quantum levels when excited, however, the atom cannot remain stable. So the the electrons return to ground state, and in the process they emit photons at characteristic frequency (light). Combination of frequency gives of 1 visible light, which can be matched to known samples.

Question 30

How is AAS used to identify different elements.

Answer 30

AAS uses the absorption spectra. A substance sample is vapourised and a light that matches the frequency of the substance you are looking for shines into the gas. If the light is absorbed, the elements present, and the concentration can be identified by however much of the light is absorbed.

Question 31

Pros and cons of AAS

Answer 31

pros: useful for identifying metals in water, or smaller samples
cons: does not work for organic compounds