Atomic Structure Flashcards
Define: atom
The smallest component of an element that can exist chemically
Not the smallest particles
consist of protons, neutrons and electrons
Define: element
Substance that cannot be split or separated into smaller or simpler substances
Simplest substances and are made up from simple particles
Consist of atoms which are all the same: either as single atoms or are bonded together
Composed of atoms that all have the same number of protons in the nucleus
Define: molecule
Smallest physical unit of an element or compound
More than one atom bonded together
Can be the same type of atom, or different atoms
Define: compound
A pure substance which consists of two or more elements chemically combined
Define: isotope
Atoms of same element with different number of neutrons
Different atomic weights
Relative atomic mass
= no. protons + no. neutrons
in nucleus of atom
ratio of the average mass per atom of the element compared to 1/12 of the mass of C-12
Atomic Number
No. protons in nucleus
No. e- in the element
proton mass and charge
1.673 x10-27
+1
neutron mass and charge
1.675 x 10-27
0
electron mass and charge
9.109 x10-31
-1
schrodingers theory of H atom
properties of waves used to explain behaviour of e-
an e- in orbit described by wave function
shows nucleus surrounded by cloud of e- density
region of space defined by the wavefunction is an orbit
define: orbit
region of space defined by the wave function of an e-
e- shells
e- arranged in successive principle energy levels
principle quantum number increases as go further out of the shells
maximum e- in 1st shell
n=1
2e-
maximum e- in 2nd shell
n=2
8e-
maximum e- in 3rd shell
n=3
18e-
e- subshells
each principle energy level split into smaller subshells
s, p, d and f
n = 1 subshells
e- = 2
1s
n=2 subshells
e- = 8
1s 2s 2p
n=3 subshells
e- = 18
1s 2s 2p 3s 3p 3d
n=4 subshells
e- = 32
1s 2s 2p 3s 3p 3d 4s 4p 4d 4f
define; orbital
each sub shell split into smaller orbitals
a region around an atom where there is high probability of finding an e- or a pair of e-
have direction, often represented on an axis
px, py, pz
s orbitals
spherical
symmetrical
found at all principle quantum numbers
contains maximum of 2e-
p orbitals
three p orbitals identical in shape
point in different directions, one facing each axis
found at n=2 and above
contains maximum 2e-
d orbitals
five d orbitals
complicated shape
found at n=3 and above
contains maximum 2e-
f orbitals
seven f orbitals
very complicated shape
found at n=4 and above
contains maximum 2e-
n=1 atomic orbitals
1s
n=2 atomic orbitals
2s 2px 2py 2pz
n=3 atomic orbitals
3s 3px 3py 3pz 3dxy 3dxz 3dyz 3dx2-y2 3dz2
n=4 atomic orbitals
4s 4px 4py 4pz 4dxy 4dxz 4dyz 4dx2-y2 4dz2
Seven 4f orbitals
define; pauli exclusion principle
each orbital contains maximum 2e-
for 2e- to occupy one orbital, spins must be paired
define: Aufbau principle
e- occupy lowest energy vacant orbital
start at lowest energy level orbital and work upwards
define: hands rule of maximum multiplicity
e- occupy set of degenerate energy orbitals by keeping parallel spins
atom in ground state adopts e- config with highest no. unpaired e-
periodic table blocks
each block names for orbital where the last e- is
s- block last e- in an s orbital etc…
