H2 Chemistry 1 - Atomic structure

p

relative charge: +1

relative mass: 1

atom position: nucleus

n

relative charge: 0

relative mass: 1

atom position: nucleus

e

relative charge: -1

relative mass: 1/1840

atom position: around nucleus

nucleus very small, compact; makes up entire mass of atom, +vely charged >

rest of atom consists empty space where e^- found >

-vely charged e^- electrostatically attracted to +vely charged nucleus >

atoms electrically neutral; e^- no. = p⁺ no.

beams of p, n, e deflect when in electric field >

straight b4 entering, parabolic path within, straight after exiting electric field >

p, +ve, deflect towards -ve plate

n, neutral, not deflected

e, -ve, deflect towards +ve plate >

angle of deflection depends on (q,charge/m,mass),

angle 2/angle 1 = (q/m)²/(q/m)¹

neutral atom; no. of +ve p = no. of -ve e^-

cation; e^- lost, no. of +ve p > no. of -ve e^-

anion; e^- gained, no. of +ve p < no. of -ve e^-

mass of atom = mass of p+mass of n = nucleon/atomic mass number

isotopes; atoms w/ same no. of p & e^-, diff no. of n >

similar chemical properties, no. of e^-, electronic config same >

diff physical properties, no. of n, mass number diff

isotopic - atoms/ions w/ same no. of p

isoelectronic - atoms/ions/molecules w/ same no. of e^-

isotonic - atoms/ions w/ same no. of n

proton number/atomic number = no. of p(neutral atom, =no. of e^-)

nucleon number/ atomic mass number = no. of p+n

larger principal quantum shell no. >

shell further from nucleus, higher energy level of e^- in shell, e^- less tightly attracted to nucleus >

sub-shells in each PQS; s,p,d,f

orbitals(each 2e^-) in each sub-shell;

s; s -> spherical

p; p_x, p_y, p_z ->2 lobes along axis

d_xy, d_xz, d_yz, d_x²-y², d_z² -> xy,xz,yz; 4 lobes b/w axis, x²-y²; 4 lobes along axis, z²; 2 lobes along axis w/ ring @ centre

3d, 4s sub-shells close in energy;

empty, energy 4s<3d

filled, energy 3d e^- repel 4s e^- further from nucleus to higher energy level

Aufbau principle; e- fill lowest energy orbitals first

Hund's rule; e- added successively to degenerate orbitals singly first w/ parallel spins b4 pairing; minimise inter-electronic repulsion

Pauli exclusion principle; each orbital max 2e^-, e^- pair opp spin

for Cu & Co, e- added to 3d first then 4s;

Cr:3d⁵4s¹ > stable than 3d⁴4s²

Cu:3d¹⁰4s¹ > stable than 3d⁹4s²

nuclear charge

as no. of proton increases, nuclear charge increases >

nuclear attraction on e- to be removed increases >

> energy req to remove valence e- > IE increases

shielding effect by inner shell e^-

shielding effect by > inner shell e^- increases >

nuclear attraction on e^- to be removed decreases >

< energy req to remove valence e^- > IE decreases

no. of principal quantum shells

radius increases, e^- removed is further from nucleus >

nuclear attraction on e^- to be removed decreases >

< energy req to remove valence e^- > IE decreases

across period

same no. of PQS, no. of e^- increases

down group

same no. of valence e^-, no. of PQS increases

across period, no. of protons increases; nuclear charge increases, shielding effect remains relatively constant >

effective nuclear charge increases, nuclear attraction on valence e^- increases >

atomic radii decreases across period

down group, no. of PQS increases, valence e^- further from nucleus >

increase in shielding effect outweighs increase in nuclear charge >

nuclear attraction on valence e- decreases >

atomic radii increases down group

cationic radii<atomic radii

cation 1 less PQS of e^-, < shielding effect >

nuclear attraction on valence e^- of cation greater, radius of cation smaller than atom

anionic radii>atomic radii

e- added to same valence shell, inter-electronic repulsion increases >

radius of anion increases > than atom

ionic radii of isoelectronic series decreases across period

across isoelectronic series w/ same electronic config, nuclear charge increases, shielding effect relatively constant >

effect nuclear charge increases, nuclear attraction on valence e^- increases >

ionic radii of isoelectronic ions decreases across period

across period no. of protons increases; nuclear charge increases, shielding effect relatively constant >

effective nuclear charge increases, nuclear attraction on valence e- increases >

> energy req to remove valence e- > 1st IE increases across period

1st IE small dip:

A;ns²>B;ns²np¹

np e- of B further from nucleus >

higher energy than ns e- of A > 1st IE of B<A

A;np³>B;np⁴

inter-electronic repulsion b/w paired np e^- in B makes it easier remove 1 of paired e- than unpaired np e^- of A > 1st IE of B<A

down group, no. of PQS increases; valence e^- further from nucleus >

increase in shielding effect outweigh increase in nuclear charge >

nuclear attraction on valence e^- decreases >

< energy req to remove valence e^- > 1st IE decreases down group

across period no. of protons increases; nuclear charge increases, shielding effect relatively constant >

nuclear attraction increases; electronegativity increases across period

no. of PQS increases, valence e- further from nucleus >

increase in shielding effect outweighs increase in nuclear charge >

nuclear attraction decreases; electronegativity decreases down group

successive e^- > difficult to remove from increasingly +vely charged ion >

when e^- removed, inter-electronic repulsion decreases, ionic radius decrease >

valence e^- > strongly attracted to nucleus >

> energy req to remove successive e^-

as e^- removed from outer shell to inner shell;

large increase b/w 2 successive IE >

2 e^- from diff PQS

moderate increase b/w 2 successive IE >

2 e^- from diff sub-shell

tendency/ability of atom to attract shared e^- in covalent bond towards itself