Fluorine because it is in the same group (group 17) as Bromine therefore it has the same chemical properties
The chemical properties of calcium are most similar to (in between) the chemical properties of magnesium and strontium.
The other members of group 17, the halogens. Specifically chlorine
Calcium and potassium
Potassium. Sodium is in group1 (period2) the next heaviest element is potassium (period 3). Potassium forms salts with the K+ ion.
A Nitrogen atom shows the most similar properties to an Oxygen atom.
The chemical properties of calcium are most similar to (in between) the chemical properties of magnesium and strontium.
The other members of group 17, the halogens. Specifically chlorine
One of the halogenss, chlorine, bromine, iodine
potatoe
Potassium - K
Se (Selenium)
Column VII A is an obsolete name; the official name of IUPAC is Group 17 (halogens group).
The periodic table is designed so elements in the vertical columns (groups) have the most similarities in chemical and physical properties. So, Iodine is most similar to the other non-metals in the Halogen family, such as Fluorine, Chlorine, Bromine, and Astatine.
1 and 2
Iodine and chlorine have very similar chemical properties because they are in the same chemical family (go see a periodic table). They are both halogens (so they have the same valence electrons).
o, s, se
Calcium and potassium