chemistry unit 1

Question 1

explain how line spectra supported Bohr’s understanding of the atom

Answer 1

it supported Bohr’s understanding that atoms have energy levels and that energy levels can change, either going up or down. and cant be between levels. Line spectra supports this because it shows that after a atom is excited it will release energy and return to ground state by emitting certain wavelengths of visible light. In line spectra you will see lines of light caused by the release of energy, they represent energy levels and change in energy levels.

Question 2

difference between Bohr model and electron cloud

Answer 2

Bohr’s model is only 2D, electrons move at constant speed in fixed orbits around the nucleus
electron cloud is a 3D model showing the most likely location of electrons in a atom. the electron cloud represents all the orbitals in the atom.

Question 3

What is electron configuration

Answer 3

how electrons are arranged around the nucleus, determines chemical behaviour of elements

Question 4

why are electrons in higher energy levels more available for bonding

Answer 4

they aren’t as attracted to the nucleus

Question 5

what are the 4 sublevels and their amount of orbitals and their shape

Answer 5

S=1 sphere
P=3 dumbbell
D=5 clover
F=7 flower

Question 6

HOW MANY ELECTRONS CAN BE IN EACH ORBITAL

Answer 6

2

Question 7

electron configuration for chlorine

Answer 7

Cl 1s2 2s2 2p6 3s2 3p5

Question 8

condensed electron configuration for chlorine

Answer 8

(Ne) 3s2 3p5

Question 9

what makes a element more metallic

Answer 9

its ability to lose electrons more willingly

Question 10

what causes outer electrons to not be as attracted to the nucleus

Answer 10

electron shielding

Question 11

why does radius decrease across a period

Answer 11

the number of protons increase, this increases the attractive pull of the nucleus to its electrons

Question 12

what is ionization energy

Answer 12

amount of energy needed to remove an electron

Question 13

what is electronegativity

Answer 13

measure of how willingly an atom can attract a bonding pair of electrons

Question 14

differ between ionic. polar and non polar bonds

Answer 14

ionic is the transfer of valence electrons, from metal to a non metal
non polar is the equal sharing of valence electrons between 2 atoms
polar is the non equal sharing of valence electrons between 2 atoms, giving each atom a partial charge

Question 15

how do you represent each type of bond(+ polyatomic)

Answer 15

ionic- electron dot
non polar- lewis structure
polar lewis structure( dipoles)
Polyatomic-lewis or electron dot with brackets and charge( no dipoles)

Question 16

what are the four exceptions to the octet rule

Answer 16

too few electrons
too many electrons
odd number of electrons
coordinate bonds

Question 17

what vsper shapes tend to be non polar

Answer 17

linear, trigonal planar, tetrahydral

NOT ALWAYS

Question 18

WHAT SHAPE IS ALWAYS POLAR

Answer 18

BENT

Question 19

what do lone pairs cause and why

Answer 19

they cause smaller bonding angles for bonding pairs
because they are closer to the nucleus they take up more bonding space and repel more strongly then bonding pairs, so they push the bonding pairs closer together

Question 20

what does polarity in a molecule determine

Answer 20

whether or not electrons are shared equally in the molecule

Question 21

what are traits of a polar molecule

Answer 21

asymmetrical
0.4-1.7
lone pair
different surronding atoms
dipoles dont cancel out creating dipole moment

Question 22

traits of non polar molecule

Answer 22

always symetrical
0-0.4
dipoles cancel out

Question 23

differ between intra and inter molecular forces

Answer 23

intra are within the molecule and a lot stronger
inter are between molecules and a lot weaker

Question 24

what are changes in state due to

Answer 24

changes in intermolecular forces

Question 25

differ between LD DD and HB

Answer 25

LD- the weakest of them all, happens when electrons are on same side of molecule, all molecules experience, strenght increase with electron amount increase
DD- when dipoles of polar molecules postion their positive and negative ends near eachother, strength increase with electronegativity increase
HB- type of DD, when hydrogen bonds with fluorine, oxygen, or nitrogen

Question 26

why are IMF’s important

Answer 26

many physical properties LIKE bp, fp, sf, v, vp are dependent on IMF

Question 27

when IMF is stronger will the boiling point increase or decrease

Answer 27

increase

Question 28

what trend is opposite out of bp, fp, sg, v and vp and why

Answer 28

vapour pressure, because when the IMF is stronger the vapour pressure will decrease

Question 29

what are energy levels

Answer 29

areas at specific distances from the nucleus where electrons are found

Question 30

what causes electrons to change energy levels

Answer 30

Energy such as heat or electricity

Question 31

how do electrons release energy

Answer 31

by emitting wavelengths of light, the light from line sprectra

Question 32

in what way do electrons fill orbitals

Answer 32

to minimize energy of atom, fill closer sublevels first

Question 33

when adding superscripts of electron configurations what should it equal

Answer 33

atomic number, amount of electrons

Question 34

compare cations and anions to there counterpart

Answer 34

ANIONS, get larger because there is a greater negative charge and aren’t attracted as strongly towards the nucleus
CATIONS, get smaller as there is less electrons the nucleus attracts the electrons closer

Question 35

what is electron shielding

Answer 35

when inner electrons reduce the nucleus charge from outer electrons