Lesson 1 revussion

The number of elements in Mandeleev's periodic table is.......elements.

• 92

• 67

• 76

• 118

Mandeleev classified the elements of each group into......... subgroups.

• 4

• 2

• 3

• 5

The scientist who left empty cells in his table to be filled with suitable discovered elements in future is........

• Mandeleev

• Bohr

• Rutherford

The modern periodic table consists of......... horizontal periods.

• 7

• 8

• 9

• 18

The number of elements that exist in nature is.......

• 118

• 92

• 67

Lanthanides ans actinides are located in the........ block.

• S

• P

• d

• f

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

• Second

• Third

• Fourth

• Fifth

The atomic number of elements equals......

• The number of neutrons inside the nucleus

• The number of protons inside the nucleus

• The nuber of electrons rotate around the nucleus

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

• S

• P

• d

• F

The element which is located in period (3) and group (3A) is......

• ₁₃Al

• ₅B

• ₁₁Na