U1- Electron arrangement and the periodic table

Question 1

*atomic radius

Answer 1

half the distance between two nuclei of a diatomic molecule, assuming a single covalent bond between two identical atoms

Question 2

core charge ( + calc)

Answer 2

measure of the net attractive force felt by valence shell electrons towards the nucleus

no. of protons in nucleus - no. of electrons in then inner shell

Question 3

how does core charge change across a period explanation

Answer 3

increases because as you go across the period, nuclear charge increases but electron shielding doesn’t change t/f increased attraction between valence e and nucleus

Question 4

how does core charge change down a group

Answer 4

stays the same because while nuclear charge increases, electron shielding equally increases

Question 5

*electronegativity

Answer 5

the strength with which atoms of an element attract electrons when they are chemically combined with another element
(large imbalances could result in covalent bond polarity or ion formation)

Question 6

how does atomic radius change across a period

Answer 6

decreases because core charge increases while the number of occupied electron shell stays the same t/f increased attraction of valence electrons to the nucleus

Question 7

electronegativity is higher when….

Answer 7

the atomic radius is low

and

the core charge on the atom is high (should be split up into nuclear charge and electron shielding)

Question 8

electronic configuration of copper

Answer 8

1s2 2s2 2p6 3s2 3p6 4s1 3d10

Question 9

electron configuration of chromium

Answer 9

1s2 2s2 2p6 3s2 3p6 4s1 3d5

Question 10

Hund’s Rule

Answer 10

Hund’s Rule of Maximum Multiplicity:
electrons in a partially filled sub shell will arrange themselves so as to form the maximum number of half filled orbitals

Question 11

Aufbau Principle

Answer 11

sub shells are filled in order from lowest energy to highest energy and that lower-energy sub shell will be filled completely before elections move into a higher-energy sub shell

Question 12

Pauli’s Exclusion Principle

Answer 12

only a max of 2 e in a given orbital and electrons will have opposite spin if orbital is filled

Question 13

*orbital

Answer 13

region of space in which up to two electrons are likely to be located. Orbitals may also be empty

Question 14

Bohr model of the atom

Answer 14

an electron in a given orbit has constant energy and
can only occupy fixed energy levels (cannot exist between two levels)

Question 15

electron shielding

Answer 15

the repulsive force exerted by inner shell electrons on outer shell electrons pushing them away from the nucleus

Question 16

sub shell

Answer 16

a subdivision of an electron shell containing a fixed no. of orbitals at the same energy level

Question 17

how many orbitals can each sub shell hold

Answer 17

s- 1 (spherical shape)
p-3 (petal shape)
d-5
f-7

Question 18

how does the light emission spectra work?

Answer 18

as an element is heated, electrons absorb energy and can be promoted to an excited state
when electron relapses to ground state a photon is released
electrons can return via different pathways each producing its own particular wavelength in the electron spectrum
the more electrons, the more relapse pathways possible

Question 19

how does atomic radius change down a group

Answer 19

increases because core charge stays the same while the number of occupied electron shell increases t/f decreased attraction

Question 20

how does electronegativity change across a period

Answer 20

increases because core charge increases while the number of occupied electron shell stays the same thus the atomic radius decreases t/f increased attraction between valence electrons and the nucleus

Question 21

how does 1st ionisation energy change across a period

Answer 21

increases because core charge increases while the number of occupied electron shell stays the same thus the atomic radius decreases, causing valence e to be more strongly attracted to the nucleus t/f more energy is required to remove an electron

Question 22

how does reactivity in metals change across a period

Answer 22

decreases because core charge increases while the number of occupied electron shell stays the same t/f increased attraction between valence e and the nucleus thus general increase in energy required to remove an electron

Question 23

how does reactivity in non metals change across a period

Answer 23

increases because core charge increases while the number of occupied electron shell stays the same thus the atomic radius decreases t/f increased attraction between valence e and the nucleus

Question 24

how does electronegativity change down a group

Answer 24

decreases because while core charge stays the same, the number of occupied electron shells increases, increasing the atomic radius t/f attraction decreases between valence electrons and the nucleus

Question 25

how does 1st ionisation energy change down a group

Answer 25

decreases because while core charge stays the same, the number of occupied electron shells increases, increasing the atomic radius as attraction between valence electrons and the nucleus decreases t/f less energy is required to remove an electron

Question 26

how does reactivity in metals change down a group

Answer 26

increases because while core charge stays the same, the number of occupied electron shells increases, increasing the atomic radius t/f attraction decreases resulting in general decrease in the energy required to remove an e

Question 27

how does reactivity in non-metals change down a group

Answer 27

decreases because while core charge stays the same, the number of occupied electron shells increases, increasing the atomic radius t/f attraction decreases

Question 28

*first ionisation energy

Answer 28

the amount of energy required to remove an electron form each of a mole of gaseous atoms (kJ mol-1)

Question 29

which group has the highest 1st ionisation energy and why

Answer 29

noble gases/ g18/ g8 because they have the highest core charge of all the elements in the same period t/f smallest atomic radius

Question 30

*relative isotopic mass

Answer 30

mass of tat isotope relative to 1/12 of the mass oof an atom of carbon-12 (ratio)

Question 31

relative atomic mass

Answer 31

average mass of isotopes of that element weighted for their abundance relative to 1/12 of the mass of an atom of carbon-12

Question 32

why does relative isotopic mass have no units

Answer 32

because it compares the mass of an atom of an isotope to the mass of an atom of carbon-12 as 12 units exactly, then this means that it is a ratio and therefore has no units

Question 33

why do alloys composed of nanoparticles produce much stronger materials

Answer 33

bc nanoparticles have a very large surface area to volume ration, them the strength of inter particle bonding increases while the spaces between particles decrease therefore creating a stronger alloy

Question 34

why do atomic radii moving across a period stay the same for transition metals eg actinides

Answer 34

bc e is added to the inner shell therefore while nuclear charge increases, electron shielding increases therefore cc stays the same tf atomic radii stays the same