Atomic Model and Periodic Table

Question 1

Atomic Theory timeline:
1803 John Dalton theorised that atoms were tiny solid spheres
1904 Thompson discovered electrons and proposed the plum pudding model
1911 Rutherford’s alpha particle experiment supports the nuclear model, mostly empty space with a dense nucleus
1913 Bohr theorised electron orbital shells
1932 Chadwick discovers the neutron and th atomic model is complete

Question 2

The relative charges of particles in atoms are :
+1 Proton
0 Neutron
-1 Electron
The number of protons in an atom is the atomic number. All atoms of a particular element have the same number of protons

Question 3

Atoms have a radius of roughly 0.1 nm(1x10 to the -10)and the nucleus has a radius of 1/10,000 of that(1x10 to the -14)

Question 4

Protons have a relative mass of 1, neutrons 1, and electrons roughly 1/1800(very small)
The sun of protons and neutrons in an atom is its mass number. Atoms of the same element can have different numbers of neutrons, these are called isotopes

Question 5

Relative atomic mass of an element is a weighted average that takes into account the abundance of the isotopes of the element. It is also roughly the mass of 1 mole of that element in grams

Question 6

Electrons in an atom occupy the lowest available shells. Each shell can contain 2,8,8,18, etc. electrons.

Question 7

The elements in the periodic table are arranged in order of proton number so that elements with similar properties are in vertical groups. Elements in the same group have the same number of outer electrons, and this gives them similar chemical properties

Question 8

Mendeleev was the first to overcome the difficulties in grouping the elements by not assuming all elements had been discovered. He left gaps for elements yet to be discovered and ended up predicting their properties

Question 9

Early periodic tables were incomplete and some elements were arranged in inappropriate groups if the strict order of atomic weights was followed. Eventually knowledge of isotopes made it possible to explain why this wasn’t always correct.

Question 10

Elements that react to form positive ions are metals
Elements that do not form positive ions are non-metals.
Metals tend to have high boiling points, be good conductors, be shiny, be malleable and ductile, and be high density.
Non-metals are the opposite

Question 11

The elements it Group 0 are the noble gases. They are unreactive due to their full outer shells. The boiling points of the noble gases increase going down the group

Question 12

The elements in Group 1 of the periodic table are known as the alkali metals and are characteristically very reactive due to the single electron in their outer shells.
The reactivity of the elements increase going down the group

Question 13

The elements in Group 7 of the periodic table are known as halogens. They are non-metals and their molecules consist of pairs of atoms. In group 7 melting point increases and reactivity decreases going down the group

Question 14

The transition elements are metals it’s similar properties different to those in group 1. They tend to have higher melting points and densities, and be stronger and harder. They are less reactive.

Question 15

Many transitions metals have ions with different charges, form coloured compounds, and are useful as catalysts