lesson 1,2 .. prep2

The scientist......discovered the main energy levels.

• a.Moseley

• b. Bohr

• c. Hofmann

• d. Mendeleev

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

• a. 67

• b. 76

• c.92

• d. 116

The scientist ..... added the zero group to Mendeleev's periodic table.

• a.Mendeleev

• b. Rutherford

• c. Moseley

• d. Bohr

Mendeleev arranged the elements of similar properties in

• a vertical periods.

• b. horizontal groups.

• c. vertical groups

• d. horizontal periods

Moseley classified elements in his table in an ascending order according to their

• a atomic weights

• b. atomic numbers

• c. chemical activity.

• d. valencies

All of the following elements are from semi-metals except

• a. tellurium.

• b. silicon.

• c. boron.

• d. bromine.

An element (Y), its atomic number is 13, so the electronic configuration of its ion is

• a. 2,8

• b. 2,8,3

• c. 2,8,8

• d. 2,8,8,3

By increasing the atomic number within the same period, the..................

• a. metallic property increases.

• b. metallic property decreases.

• c. nonmetallic property decreases.

• d. atomic size increases.

An element (X), its atomic number is 15, so the number of electrons in its ion equals

• a. 10

• b. 15

• c. 17

• d. 18

All of the following ions have the same electronic configuration of neon (10Ne) except

• a. A1+3

• b. Na+

• c. Li

• d. Mg+2