atomic structure, isotopes + periodic trends

Question 1

What is the nucleus of an atom made up of?

Answer 1

protons (+) and neutrons (neutral/no charge)

neutrons help keep all the particles in the nucleus strongly connected to each other

Question 2

how is the nucleus and electrons related?

Answer 2

electrons are negatively charged and they are attracted to the positively charged protons in the nucleus

Question 3

Protons, neutrons, electrons –which weights the least?

Answer 3

electrons (-)

Question 4

Atomic number (Z)

Answer 4

number of protons in the nucleus of an atom.
- the number of protons in an atom tell us what kind of atom it is (carbon, oxygen etc)

Question 5

Mass number (A)

Answer 5

Number of protons + neutrons in the nucleus of an atom

Question 6

Net charge

Answer 6

How protons and electrons balance each other out.

Question 7

What is an ion

Answer 7

an ion is any atom, that has a net charge

Question 8

Neutral ion problems

Answer 8

The number of electrons in a neutral atom is equal to the number of protons.

The mass number of the atom (M) = the number of protons + neutrons

The number of neutrons is = mass number of the atom (M) - atomic number (Z).

Question 9

Isotopes

Answer 9

Same amount of protons, different amounts of neutrons.

different versions of an atom

isotopes have the same properties because they have the same number of electrons in their outer shell.
- CHEMICAL properties depend on e-

Question 10

group 7:halogens

Answer 10

all group 7 elements form a molecule consisting of 2 atoms joined by a covalent bond

they are hence, diatomic (F2, I2, Cl2 etc)

Question 11

halogen trends

Answer 11

melting and boiling points increase the further down you go

reactivity decreases as you go down (bc e- further away from nucleus, and the gain electrons faster)

Question 12

Displacement halogen reaction

Answer 12

A more reactive halogen can replace a less reactive halogen from an aqueous solution of its salt.

i.e Cl2 (aq) + 2KBr(aq) –> 2KCI + Br2

chlorine has replaced bromine

Question 13

Noble gases

Answer 13

all exist as COLOURLESS gases
- inert (don’t react, due to their full outer shells)
- non-flammable
- exist as single atoms

boiling point increases as you go down the group

Question 14

Noble gas uses

Answer 14

Helium: balloons
Neon: making lasers
Argon: filling household lamps
Krypton xenon: low power lamps, specialised lamps
Radon: radiotherapy