Define the number of electrons on the outer shell of the atoms in the following elements: – a) 13 Al 2e 8e … – b) 17 Cl 2e 8e … – c) 20 Ca 2e 8e 8e … 3. Look at the periodic table. How many electron s

Define the number of electrons on the outer shell of the atoms in the following

elements:

– a) 13 Al 2e 8e …

– b) 17 Cl 2e 8e …

– c) 20 Ca 2e 8e 8e …

3. Look at the periodic table. How many electron shells are there in:

– a) the 7 th element

– b) the 10 th element

– c) the 16 th element

– d) the 20 th element

4. Which elements have the following electron configurations?

– a) 1s 2 2s 1

– b) 1s 2 2s 2

– c)1s 2 2s 2 2p 3

– d) 1s 2 2s 2 2p 6