Chemistry Ib Hl : 1.3 - Electron configurations

continuous line spectrum vs emission line spectrum

A continuous spectrum shows all the wavelengths or frequencies of visible light whereas an emission line spectrum has only certain wavelengths or frequencies (or colours) shown on a black background.

orbital

a region around an atom with a high probability of finding an electron

why are S electrons lost first in transition metals

• furthest from the pull of the nucleus

• have higher energy ( easier for them to whoop out )

things which make ionisation energy decrease

• the distance of the electron from the nucleus: the closer, the stronger the force of attraction

• shielding from full shells of inner electrons ( make it so that the positive charge felt by the on the valence shell electrons is the charge of the protons- charge of the full inner shells)

• size of the nucleus - a larger nucleus signifies a stronger nuclear force

first ionisation energy equation

X(g) => X^+1 (g) + e^-1

why is a logarithmic scale used for graphs of ionisation energies .

because the range of these energies is huge and it wouldn’t be possible to visualise on a single graph

why are ionisation energies in the same atom getting greater the more electron are getting taken away

• because the ion is becoming more and more positive, there is an increase in the electrostatic attraction between the nucleus and the remaining electrons and an increase in the ionisation energy.

• electron repulsion is weaker as there are less electrons in that energy level

net nuclear charge

nuclear charge of nucleus- charge of inner shells

variations inside a period

the (p or d ) orbital is higher energy than s, so less stable and it is easier to take away

variations in ionisation energy in the same periods

differences in energies in the orbital: energy in S is smaller than in P, and in D bigger than in P.

why is the first ionisation of energy of helium much higher than that of hydrogen

outer electrons are in the same energy level

but helium has a higher nuclear charge than nitrogen

why first ionisation charge of lithium lower than of Helium even if nuclear charge is greater in lithium

the higher nuclear charge of lithium is offset by the shielding of the 2 inner electrons. this results in the outer electrons of helium having a greater force of attraction to the nucleus

why are the noble gases the most stable in their periods

• they have the highest nuclear charge in the group

• while still having the same amount of shielding compared to other group 2 electrons

why do atoms with double occupied orbitals have a lower ionisation energy

An electron in a doubly occupied orbital is repelled by the second electron and requires less energy to remove than an electron in a half-filled orbital.

atomic mass of an element

the weighted average of the masses of the isotopes relative to 1/12 of the mass of a carbon-‐12 atom.

first ionisation energy

the energy required to remove one mole of electrons from one mole of gaseous atoms to provide one mole of gaseous single charged ions.

what do you say when asked about information of electronic configuration

• how many energy levels

• how many valence electrons