Attempts of Elements Classification

The chemical properties of calcium

(₂₀ Ca) are similar to those of .......................

• ₁₉K

• ₁₂Mg

• ₂₅Mn

• ₃Li

The element (₁₂X) is located in ................. in the periodic table.

• period (2) and group (2A)

• period (2) and group (3A)

• period (3) and group (2A)

• period (3) and group (4A)

The atomic number of an element that exists in group (7A) and period (2) is .........................

• 12

• 7

• 9

• 17

The element whose atomic number (18) is .........................

• transition element

• inert gas

• metallic element

• halogen element

In the periodic table, the elements which are similar in their properties and located in the same ................

• period

• group

• nucleus

• energy level

The number of negative electrons in the atom in its normal state equals .............

• the number of protons.

• the number of neutrons.

• twice the number of protons.

• half the number of neutrons.

Elements of d-block are arranged in ..................... groups.

• 2

• 5

• 6

• 10

The block which contains the group (1A) and (2A) in the periodic table is ......... block.

• s

• p

• d

• f

The transition elements start to appear from the beginning of the ................. period.

• second

• third

• forth

• fifth

The scientist, who discovered that the nucleus of atom contains positively charged protons is .............

• Bohr

• Mendeleev

• Rutherford

• Moseley