Topic 1

Question 1

Basic structure of atoms

Answer 1

-fundamental building blocks of matter
-3 subparticles :electron, proton & neutron
-p(+) & n (n/a) are in the nucleus
-e (-) orbit the nucleus arranged in energy levels or orbitals

Question 2

Atomic number and mass number

Answer 2

i.Z-refers to the number of protons in nucleus, used to identify element because each is unique
ii. A- p + n in nucleus

Question 3

Elements and compounds

Answer 3

-elements: pure substances with atoms of sma atomic number, listed on periodic table & cant be broken down into small thing by chemical mean
-compounds: 2 or more elements combines in fixed ratios e.g H20

Question 4

isotopes

Answer 4

atoms of the same elements with the same number of protons but different mass number i.e p + n
same chemical properties but stability & nuclear properties maybe diff
e.g 1H-protium, 2H-deuterium , 3H-tritium

Question 5

Radioactivity:

Answer 5

refers to th emission of radiation from nucleus
comes from radioactive compound snamed isotopes

types of radiation emitted:

i.alpha: has He nucleus so 2p & 2n, positive nucleus, heavy mass, lower penetration power

ii. Beta: + & -, has ligher mass than alpha, slight penetration power can go through skin

iii.Gamma: photons, masselless, high penetration power

Question 6

Avogadro’s number

Answer 6

-Na
-refers to a fundamental constant represention no of atoms or molecules in 1 mole of substance
value is 6.022 X 10 ^ 23

Question 7

def of mole

Answer 7

Quantify the amount of substance
so 1 mole has Na of particles, can be atoms ions or entities

Question 8

electronic sturcture of atoms

Answer 8

refers to arrangement of electrons on atoms. They are arranged in specifc levels or shells each with a max. no electrons.
Electronic structure determines chemical & physical properties

Question 9

Building up principle

Answer 9

also known as aufbau’s principle-it guides on how to fill up electron orbitand and it states the lowest energy orbitals must be filled it first before the higher energy orbitals

–remember arrow drawing

Question 10

Quantum numbers

Answer 10

-describes characteristics & proton in atom
-there is

n-principal quantum number: energy level or shell / possibble values - positive integers

l- angular momentum quantum number: shapes of orbital so
if l=0 its s-orbital (spherical)
if l = 1 – p-orbital (dumbell)
if l = 2 – d-orbital (cloverleaf)
if l = 3 — f-orbital (complex shapes)

mL; magnetic quantum number / orientation of orbital in space so possible values : -l to + l including zero

ms ; spin quantum number : the spin direction wether positive or negative / possible values : -1/2(“spin-down.”) or + 1/2(“spin-up”)

Question 11

atomic orbitals

Answer 11

regions around the nucleus where electrons are likelt to be found. 4types:
1. s-orbital: spherical shape/ can hold up to 2 electrons
2. p-orbital : dumbbel shape/ up to 6 electrons, has 3 orientations: -1,0,1
3. d-orbital: cloverleaf shaped/ up to 10 electrons/ 5 orientations : -2, -1 , 0 ,1,2
4. f-orbitals: complex shapes/ up to 10 electrons/ 7 orientations

Question 12

Pauli exclusion rule

Answer 12

No 2 electron in an atom can hold the same set of qunatum numbers i.e an orbital can hold a max of 2 electrons with opposite spins

Question 13

Hund’s rule

Answer 13

(the box rule)

so electrons occupy separate orbitals of the same energ before pairing up in smae orbiatal hence there are un paired electrons in different orbitals which maximizes total spin & stabilizes atom

Question 14

periodic table

Answer 14

tabular arrangement of element based on atomic number & electron configuration

Question 15

periodic properties: relationship to electron configuration

atomic radius

Answer 15

Across a Period: As you move from left to right across a row, atoms get smaller. This is because more protons in the nucleus pull electrons closer.

Down a Group: As you move down a column, atoms get larger. This is because more electron shells are added, making the atom bigger.

Question 16

IE relationship to electron configuration

Answer 16

Across a Period: It takes more energy to remove an electron from an atom as you move from left to right. This is because the atoms are smaller and hold onto their electrons more tightly.

Down a Group: It takes less energy to remove an electron from an atom as you move down a column. This is because the atoms are larger and hold onto their electrons less tightly.

Question 17

EN relationship to electron configuration

Answer 17

Across a Period: Atoms attract electrons more strongly as you move from left to right. This is because the atoms are smaller and have a stronger pull on electrons.

Down a Group: Atoms attract electrons less strongly as you move down a column. This is because the atoms are larger and have a weaker pull on electrons.

Question 18

Electron affinity

Answer 18

Across a Period: Atoms release more energy when they gain an electron as you move from left to right. This is because the atoms are closer to having a full outer shell.

Down a Group: Atoms release less energy when they gain an electron as you move down a column. This is because the atoms are larger and the added electron feels less attraction from the nucleus.

Question 19

Metallic caracter

Answer 19

Across a Period: Atoms become less metallic as you move from left to right. This is because they hold onto their electrons more tightly.

Down a Group: Atoms become more metallic as you move down a column. This is because they lose their outer electrons more easily.