Get Started. It's Free
or sign up with your email address
Chemistry Topic 1 by Mind Map: Chemistry Topic 1

1. Periodicity

1.1. I.E across a period

1.1.1. He>H

1.1.1.1. nuclear charge is greater,one extra proton

1.1.2. Li<He

1.1.2.1. increased nuclear charge but outer electron is held less strongly, sheilded by inner full levels ans is further away

1.1.3. Be>Li and Mg>Na

1.1.3.1. increased nuclear charge

1.1.4. B<BE and Al<Mg

1.1.4.1. despite increased nuclear charge, outer electron is held weaker, shielded by 2s energy sub-shell, also further away

1.1.5. O<N and S<P

1.1.5.1. despite increased nuclear charge, in N the electron is in 2s sub-shell, in O there are 4 electrons in the same sub-shell

1.1.6. Na<Li

1.1.6.1. despite increased nuclear charge, increased shielding and grater distance from nucleus is there. so outer electron is held less strongly in Na so it is easier to remove.

2. Relative atomic mass- the masss of an atom relative to c-12 having a value of exactly 12.00

2.1. Relative isotopic mass, similar but uses an isotope

2.2. relative molecular mass, same but uses mass of the molecule

2.3. relative formula mass, used for any formula of a species or ion

3. Characteristics of sub-atomic particles: Electron: mass of 1/1840, charge -1 Proton: mass of 1, charge 1 Neutron: mass of 1, charge 0

4. Atomic structure

4.1. Definitions

4.1.1. Atomic number- number of protons in the nucleus

4.2. isotope- same atomic number different mass number

4.2.1. mass number- number of protons + the number of neutrons

4.3. mass spectrometry- the process used to identify the relative atomic mass of an element, the the process of vapourising the substance, then ionisation, acceleration, deflection then finally detecting the relative atomic mass of the element

4.4. Mass spectra- show the results on a graph where it is the relative abundance on the y-axis and the m/z value along the x- axis. this allows us to detect which element it is, as the point with the largest peak is the point where the most common isotope of that certain element is found.

5. Electronic configuration

5.1. Orbital- a region of space where one is likely to find an electron, each orbital can hold up to two electrons, with opposite spin

5.2. types of sub-shells, s sub-shell can hold 2 e-, shape is spherical. p sub-shell is a dumbbell shape and can hold up to 6 e-

5.3. Filling order- 1s,2s,2p,3s,3p,4s,3d,4p,5s,4d,5p,6s,4f,5d

5.4. Evidence-

5.4.1. Energy levels, periodically there was a large drop in the energy to remove the electron by the electrons being further from the nucleus

5.4.2. Sub-levels- the energy required to remove the electron was sometimes less than expected due to shielding from filled sub-levels

5.5. ionisation energy

5.5.1. a measure of the energy to remove an electron from an atom

5.5.2. value depends in the distance of the electron from the nucleus

5.5.3. there are as many ionisation energies as there are electrons in the atom

5.6. nuclear charge- the actual charge due to protons in the nucleus

5.7. effective nuclear charge- the effectiveness of the nuclear charge after all the shielding and distance from nucleus

5.8. 1st I.E- the energy required to remove one mole of electrons from one mole of gaseous atom to form one mole of gaseous positive ion.