Electron structure Flashcards
define electron shell
the orbit that an orbital is in around the nucleus of an atom
define electron configuration
the arrangement of electrons
define atomic orbital
a region around the nucleus that can hold up to two electrons with opposite spins
what are the different types of orbitals
s-, p- , d- , f-
what’s the valent shell
the outermost one
the further the electron is from the nucleus, the ……………. the energy level
higher
what’s principle quantum number
the number, n, used to number the energy levels
how many electrons can the first shell hold
2
how many electrons can the second shell hold
8
how many electrons can the third shell hold
18
how many electrons can the fourth shell hold
32
how do you work out maximum number of electrons in shell
2n^2
n = principle quantum number (shell number)
define first ionisation energy
energy required to remove 1 mole of electrons from 1 mole of gaseous atoms to form gaseous 1+ ions
A (g) —> A+(g) + e-
IE1 is ……… when an e- is removed from a higher energy level
- lower
- decreasing IE1 consistent with increasing energy levels
define successive ionisation energy
energy required to remove each electron one by one from 1 mole of gaseous atoms/ions
what factors affect ionisation energy
- the greater the attraction between the e- and the nucleus the higher the IE
- atomic/ionic radius
- nuclear charge
- shielding - outer and inner e- repel, less attraction
why is the IE2 of calcium and strontium greater than IE1
- the elements become more ionised (less e- so less repulsion)
- smaller ionic radius so greater electrostatic forces of attraction
- increased nuclear charge
what’s the evidence for change of sub shell
small jumps in IE
shape of s orbital
spherical
shape of p orbital
dumb-bell
how many orbitals are in the s subshell and how many e- can it hold
- 1, s orbital
- holds 2 e-
how many orbitals are in the p subshell and how many e- can it hold
- 3, p orbitals
- holds 6 e-
how many orbitals are in the d subshell and how many e- can it hold
- 5, d orbitals
- holds 10 e-
how many orbitals are in the f subshell and how many e- can it hold
- 7, f orbitals
- holds 14 e-
what does each subshell consist of
orbitals of the same type
4d…
fills first and empties first
what’s the evidence for change of shell
large jumps in IE
there’s extra stability from ….. or ….. subshell
filled or half filled
Hund’s rule
e- are added to orbitals singly with parallel spins before orbitals are occupied in pairs
the most stable electronic configuration of an atom has the …. amount of energy
lowest
what are the elements whose e- configuration are exceptions
- Cu
- Cr
why does Cu have its unexpected e- configuration (involves 4s and 3d)
- Cu : 1s^2 2s^2 2p^6 3s^2 3p^6 4s^1 3d^10
- half filled 4s and fully filled 3d provide more stability
why does Cr have its unexpected e- configuration (involves 4s and 3d)
- Cr: 1s^2 2s^2 2p^6 3s^2 3p^6 4s^1 3d^5
- half filled 4s and 5d provide more stability
