lesson 1 part1 g8

1-The number of elements in Mendeleev's periodic table is .............................

elements.

• a. 92

• b. 118

• c. 76

• d. 67

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

• a. Moseley.

• b. Rutherford.

• c. Bohr.

• d. Mendeleev.

3. Mendeleev classified the elements of each main group into .......... subgroups.

• a- 2

• b- 3

• c- 4

• d. 5

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

• a. Bohr

• b. Mendeleev.

• c. Rutherford.

• d. Moseley.

5-The nucleus of the atom contains ............................

• a. positive electrons.

• b- negative protons.

• c- negative electrons.

• d. positive protons.

6-The scientist ............................... discovered the main energy levels of the atom.

• a. Moseley

• b. Bohr

• c. Hofmann

• d. Mendeleev

7-The number of energy levels in the heaviest known atom reaches ......................evels till now.

• a- 5

• b- 7

• c- 8

• d- 10

8- The number of known elements in the modern periodic table till now is............................

• a. 216

• b. 118

• c. 316

• d -16