Lithium (Li)
The element with 4 electron shells is potassium (K).
The atomic number of the element with the symbol Be (Beryllium) is 4.
berylium has 4 protons. It has 4 electrons too.
Element Phosphorus has an oxidation state of -4. No element has oxidation state of +4. Phosphorus is denoted by "P".
The element in period 4 of the Periodic Table with the highest electronegativity is krypton (2.96). The period 4 element with the lowest electronegativity is potassium (0.82).
The element in period 4 group 2A is calcium (Ca).
Be
element K, or potassium
Br (Bromine) is a period 4 element in the same group as F.
There is no element with 28 protons in group 4. I think you are getting confused with group 4 and PERIOD 4. In period 4, the element with 28 protons is Nickel.
Iron (Fe) is the element that has 4 unpaired electrons in its electron configuration.
Iron is a brittle metallic element. On being struck sharply by say, an hammer, it will shatter into sharp angular pieces. NB Iron has to be in the pure solid state to do this. If alloyed or impure , it tends not to shatter. Gold, Lead, and Zinc are much softer metals and do not shatter on being struck by an hammer