How is beryllium (Be) similar to calcium (Ca)?​

Explanation:

beryllium, calcium, strontium, barium, and radium; they are in the same group of table.

Both Beryllium and Calcium have 2 valence electrons, i.e. in ther electronic configuration there are 2 electrons remaining in the outermost shell.  Thus their valencies are also 2.

Electronic Configurations:

Beryllium (4) : - [2, 2]

Calcium  (20) : [2, 8, 8, 2]

Hope it helps

Thank you for the question

Edit

a. both are very reactive

b. both react readily with elements in group 1

c. both rarely combine with other elements

d. both are rare metals

(As per the suggestion of bvbfanforeverap5j54d)