Reaction Rate is the rate at which a substance undergoes a chemical change.
The atomic radius increases down a column (group) and decreases along a row
is the Calcium
because the calcium in group two which group two has 2 electron and also calcium and Potassium 4s sub level group potassium has 1 electron. :)
Group 1 and group 7 of element group consists of alkali metal, which are generally combined with other elements in nature, so they have properties of compound
