Class Notes (995,956)
CA (574,558)
Western (59,278)
2123A/B (13)
Lecture 2

Earth Sciences 2123A/B Lecture 2: Periodic Table and Sun fusionPremium

4 pages82 viewsFall 2016

Department
Earth Sciences
Course Code
Earth Sciences 2123A/B
Professor
Catherine Neish
Lecture
2

This preview shows page 1. to view the full 4 pages of the document.
Lecture 2 – Periodic Table and Sun Fusion
Dimitri Mendeleev
1871 he published a periodic table of elements and predicted the properties of 3 new elements
oGallium, Scandium and Germanium
Properties of elements are periodic functions of their atomic weight
There are trends or patterns in the properties of the elements and these are related to their atomic
weight and associated electron structure
Periodic Law
1. From left to right across a period / row – electrons are being added to the same energy level and
protons are being added to the nucleus
oThe electrons in the outer energy level are, therefore attracted more strongly and so are pulled
closer to the nucleus
oAtomic size is decreasing
2. Moving down in a group, it starts to fill more energy levels
oThe outermost electrons become less tightly bound to the nucleus
oAtomic size is increasing
3. Elements tend to gain or lose outermost- valence electrons to achieve stable filled octet formation –
this makes those multiples of 8 electrons very stable – the inert / noble gases of group VIII
Atomic radius – half the distance between the centres of two atoms that are just touching each other
Ionization Energy – amount of energy required to completely remove an electron from a gaseous
atom
oThe closer and more tightly bound an electron is to the nucleus, the more difficult is to remove
and the higher its ionization energy is
Electron Affinity – the amount of energy released when an electron is added to a neutral atom or
molecule to form a negative ion
Electronegativity – the tendency of an atom to attract electrons
Molecules
Molecules are two or more atoms joined together by chemical bonds
oThe molecular weight is the sum of the atomic weights
oThus, one of mole of water weights – 2x (1.01g/mol H) + (16.00g/mol O) = 18.0g /mol H2 O
Another example – CaCO3 or calcite – mineral name
oLimestone rock is made up of mainly the mineral calcite
oThe molecular weight is the sum of the atomic weight
find more resources at oneclass.com
find more resources at oneclass.com
You're Reading a Preview

Unlock to view full version

Subscribers Only

Only page 1 are available for preview. Some parts have been intentionally blurred.

Subscribers Only
You're Reading a Preview

Unlock to view full version

Subscribers Only

Only page 1 are available for preview. Some parts have been intentionally blurred.

Subscribers Only
You're Reading a Preview

Unlock to view full version

Subscribers Only

Only page 1 are available for preview. Some parts have been intentionally blurred.

Subscribers Only
You're Reading a Preview

Unlock to view full version

Subscribers Only

Loved by over 2.2 million students

Over 90% improved by at least one letter grade.