CC4- The Periodic Table

Question 1

Describe Mendeleev’s periodic table

Answer 1

• he arranged his periodic table in increasing relative atomic mass
• with this, he found that elements with similar properties would be in the same column
• however with doing this, he found that some elements in the same column did not have the same properties, so to keep elements with similar properties together he left gaps for undiscovered elements

Question 2

Describe the periodic table today.

Answer 2

• The periodic table today put elements in increasing atomic number
• It is laid out so elements with similar chemical properties, form columns (groups)
• The group that the element belongs to corresponds to the number of electrons, it has in its outer shell (apart from group 0 elements which have a full outer shell)
• The rows (the horizontal ones) are known as periods. Each new period represents another shell of electrons so the period that an element belongs to corresponds to the number of shells it has

Question 3

How is are electrons configured?

Answer 3

• the first shell will have two electrons and after this, the shells can have up to 8

Question 4

How do you workout the electron configuration?

Answer 4

• The electron configuration of an element can be worked out from its atomic number
• The first shell will occupy two electrons, and after this, they can occupy up to 8
• for example, chlorine has 17 protons. Therefore it has 17 electrons and its electron configuration is 2,8,7