Atomic Structure Flashcards
Name 3 sub atomic particles, their location, mass and charge
Protons, nucleus, 1, +1
Neutrons, nucleus, 1, 0
Electrons, electron shells around the nucleus, 1/2000, -1
Define atomic number
Number of protons in an atom
Defines element
Define mass number
Number of protons and neutrons in an atom
Defines isotope
Does atomic number or mass number go at the top
Mass number
Define an isotope
Atoms with the same number of protons/atomic number but different number of neutrons/mass number
Define relative isotopic mass
The average mass of one atom in a sample of one isotope of an element only on a scale where one atom of C-12 is 12 units exactly
Define relative atomic mass
The average mass of one atom in a naturally occurring sample of an element on a scale where one atom of C-12 is 12 units exactly
Which formula mass should be used for giant structure compounds
RFM
Units g/mol
Describe the process of mass spectronomy
Sample vaporised
Particles pos ionised by electron gun (knocks of electrons)
Positive ions accelerated
Pass through neg charged grid
Curved mag field (curved mag poles)
Deflect smallest/most charged ions easiest
Detector has a m/z ratio
Records no.ions/ratio
Ratio is changed to count different partciles
Describe a mass spectronomy graph
Y axis: relative intensity
X axis: m/z (z usually 1 but CHECK)
Can be 2 clusters of peaks (parent ions and fragments)
Eg. Ionised Cl2 molecules and fragmented Cl molecules
Describe how to calculate RAM
Eg. Cl
(Relative intensity x mass number) + (“”) / 100
Describe how to calculate relative abundance of isotope
Eg. Chlorine
Fragments: read straight of graph, make ratio
Parent ionised molecules: all combinations, combined mass number, x relative abundances of atoms, combine any same, find probability as a percentage
State 2 things that can happen when an atom gains energy
Speed up
Excitation
What is a ground state atom formation
Most stable, normal arrangement o electron
Only ever 1
Electrons held in place by ESA with nucleus
What is excitation
Electron moves away to a shell further from the nucleus
Energy absorbed to overcome ESA
Many different excited states
Larger distance = layer excitation
Unstable
What is relaxation
Electrons drop back down from excited state
Release energy, photons of light (EMR)
Shine through, series of lines, match light of a specific wavelength
What binds an electron the nucleus
Fixed energy caused by ESA between neg charged electron and pos charged nucleus
Describe the Lyman series on a line emission spectra graph
N=1
High energy
Low wavelength
UV spectrum
Not visible
Describe the Balmer series on a line emission spectra graph
Only visible series
Followed by further relaxations
Describe the Paschen and Brackett series on a line emission spectra graph
Infrared spectrum
Non visible
Low energy
High wavelength
Followed by further relaxations
What do arrows on a line emission spectra graph represent
Possible relaxations
Large length = large energy lost
What is an electron address
Exact position in cloud of electrons
Principal shell: size of region
Sub shell: shape of region
Orbital: orientation of region
Spin: up/down
Describe the patterns of sub shells and principal shells
N=3 has 3 sub shells
S, p, d, f
What is an orbital
A region within an atom that can hold up to 2 electrons with opposite spins
Describe the shape, number of orbitals and electrons in each subshell
S, spherical, 1, 2
P, bow tie, 3, 6
D, clover, 5, 10
F, -, 7, 14
Describe electron configuration, shortcuts, exceptions and what they show
2s2
PS=2
SS=s
No.es=2
4s precedes 3d
Shorten using noble gases [Ne]
Exceptions: Cu,Cr (4s1)
They determine chemical properties of an element
State 2 rules for electrons in boxes
Fill sub shells stay before pairing up
2 electrons in same box must spun in opp direction
Describe the ‘block’ of elements
Block indicates subshell outer electron is in
S block= G1,2 + He,H
D block= transition metals
P block= G3-0
F block= ones at bottom
Describe ionisation
Orbitals get closer together
Eventually converge
Give electrons energy
Pass convergence
Electron lost
Atom becomes ion
Always an endothermic reaction (+Kj/mol)
Define ionisation energy
Minimum energy required to remove 1 electron from each atom in a mole of atom sin the gas state
Units=Kj/mol
Describe successive ionisations
Atoms with more than one electron (not H)
Each ionisation removes 1 atom
IE increases arch time
Describe patterns in an IE graph of one atom
Large increase between principal shells (decrease shielding, despite increased ESA)
Small increase across principal shell (shielding approx constant, decrease ESR)
What 2 forces determines the binding of an electron to an atom
ESA between neg e and pos nucleus
ESR between neg electrons
Define shielding
Reduction in ESA between e ad atom nucleus due to es in inner shells blocking the full force
Name 4 patterns in first IE graphs
Increases mostly across period
Decreases between periods
Decreases don a group
2 small decreases across a period
Why does IE mostly increase across period
Increase no.protons/nuclear charge
Increase ESA
Es held tighter
Despite shielding approx constant
Decrease in steepness/period
Why does IE decrease between periods
Ionise from new outer principal shell
Increase shielding
Es held looser
Despite increased nuclear barge/ESA
Why does IE decrease down a group
increased shielding
Increased distance from nucleus
decreased ESA
Despite increased nuclear charge/ESA
Why does IE decreased between group 2 and 3 element
Ionising from a new p subshell
Looser bound than s
Further from nuclei, decreased ESA
Why does IE decrease between group 5 and 6
Ionise from doubly occupied p orbitals
Increased ESR
Define periodicity
A property that follows a recurring pattern through the periodic table
Name 3 periodicity patterns
Atomic radius
Mp/bp
Electronegativity
Explain periodicity of atomic radius
Decreases across period, increased nuclear charge/ESA, despite approx constant shielding, es held tighter
Increases between periods, new principal shell, increased shielding, despite increased nuclear charge/ESA
Cations < atom < anion
Explain periodicity of melting point/boiling point
High values: giant structure
Low values: simple molecular, lack of bonding
Bp is the same but slightly higher values
