Atom

Question 1

What is the Thomson model of an atom?

Answer 1

Plum pudding! 1900 ish! Ball of positive matter dotted with negative electrons! Like a plum pudding!

Question 2

What is Rutherfords atom model?

Answer 2

1911, a tiny dense positively charged core called a nucleus in which nearly all mass is concentrated around which light negative constituents (electrons) circulate around. This was found through the gold foil experiment where electrons were fired at a thin gold foil.

Question 3

Bohr Atomic Model?

Answer 3

1913, first to include how light was produced through electrons moving up and down shells.

Question 4

Chadwick’s atom model?

Answer 4

1932 finds Neutrons! Used similar experiment as rutherfords.

Question 5

What is an isotope?

Answer 5

Isotopes are variations of the same element with a dif. Numbers of neutrons and dif masses. But the same number of protons and electrons so they have similar reactions

Question 6

What is relative atomic mass?

Answer 6

The weighted mean mass of an element relative to 1/12th of the mass of C-12.

Question 7

What is the equation for RAM?

Answer 7

(%abundance x mm) + (%abundance x mm)/ 100

Question 8

What is mass spectrometry?

Answer 8

Measure the masses of atoms and molecules

Question 9

How do you predict mass spectra?

Answer 9

Only do this for diatomic molecules!

1) convert % to decimal
2) create table and fill in (punnet square)
3) identify same molecules
4) divide by smallest
5) plot!

Question 10

How do we find the exact mr using spectra?

Answer 10

Use molecular ion peak that is furthest to right, also need to know about all the dif. Isotopes of that element.

Question 11

How does mass spectrometry work?

Answer 11

The atoms are hit with a beam of high energy electrons that knock the another electron off to leave a pos ion. 1)Vaporisation- sample is made a gas, 2) Ionisation- Hit with a beam of highe energy electrons, 3) Acceleration- particles propelled forward using em fields, 4) deflection- smaller particles deflected more by mag. Field, 5) detection - position depends on deflection

Question 12

What is the relationship between energy in a shell and distance from the nucleus?

Answer 12

As distance increases energy increases.

Question 13

What is an orbital?

Answer 13

A region of space where you are likely to find pairs of electrons

Question 14

What type of shells are there?

Answer 14

S P D F

2 in S
6 in P
10 in D

Question 15

What elements are exceptions to electron configuration rules?

Answer 15

Chromium = 1s2 2s2 2p6 3s2 3p6 3d5 4s1
Copper = 1s2 2s2 2p6 3s2 3p6 3d10 4s1

Why? Energy levels close in energy
Chr= no electrons started to pair up all single shells
Cu= 3D Full with 4s chillin
No partially full orbits

Question 16

How is light produced?

Answer 16

Electrons get excited and move up an energy level, they then drop back down to ground level releasing a photon, releases a frequency dependent on how excited, combinations of frequencies make dif colours.

Question 17

What is First Ionisation Energy?

Answer 17

Energy required to remove 1 electron from each atom in 1 mole of gaseous atoms to form 1 mole of gaseous 1+ ions

Question 18

How does atomic radius affect 1st ionisation energy?

Answer 18

More shells an atom has further away the outer electrons are and less attraction they experience.

Question 19

How does nuclear charge affect how great 1st ionisation energy is?

Answer 19

More protons mean new more nuclear charge and therefore more attraction to outer electrons

Question 20

How does shielding affect 1st ionisation energy?

Answer 20

Number of electrons between nucleus and outer shell grows the outer electrons feel less attraction to the nucleus lowering the energy required to ionise it.

Question 21

What are the trend in ionisation energies?

Answer 21

It decreases down a group

It increases across a period.

Question 22

How do you explain the anomalies in ionisation energies for gr 2&3?

Answer 22

P orbitals are marginally further than s from the nucleus. There is also slightly more shielding so anomalies can be lost more easily leading to small drop in ionisation energy

Question 23

How do you explain the anomalies in ionisation energy for groups 5&6?

Answer 23

Shielding is similar. But as they are starting to pair there is repulsion between them so the electrons are lost much more easily leading to a small drop in 1st ionisation energy.

Question 24

Why does ionisation energy increase with more electrons removed?

Answer 24

It becomes harder to remove electrons due to the positive charge remaining constant whilst the negative grows weaker (nuclear charge)

Question 25

What is successive ionisation energy?

Answer 25

The energy needed to remove 1 electron from each ion in 1.

Mole of gaseous 1+ ions to form 1 mole of gaseous 2+ ions.

Question 26

What can you work out if you have a list of the successive IEs of an element?

Answer 26

The group the element is in! How many energies before 1st BIG jump!

Question 27

What is the trend of Mp/Bp on the periodic table?

Answer 27

Increases across groups 1 2 & 3 (metals) peaks at 4 ( due to being giant covalent), 5 6 7 remain fairly constant, 8 lower as noble.

Question 28

Why does mbp increase along groups 123?

Answer 28

An increase in charge causes an increase in boiling point due to stronger electrostatic forces of attraction holding the molecules together.

Question 29

Why does mbp peak at group 4?

Answer 29

Very strong strong covalent bonds in a giant covalent structure require A Lot of energy to over come.

Question 30

Why does MBP decrease in later groups?

Answer 30

They tend to be simple covalent molecules and as such have weak London forces that require little energy to overcome.

Noble gasses are monoatomic and as such have very weak London forces between molecules so BMP ist lowest!

Question 31

What is the trend of atomic radius along the periodic table?

Answer 31

Across the period Atomic Radius gets smaller, little increase in shielding and distance between nuclei , nuclear charge outweighs this!