Prep 2 - Science - Prepared by Mr. ASHRAF MOSA MOHAMED

Elements are arranged ascending according to their atomic weights in ............

• Modern periodic table

• Mendeleev’s periodic table

• Moseley’s periodic table

Complete :

The number of known elements until now are ......... elements

Complete :

The number of elements are abundant in the earth’s crust = ...........

Advantages of Mendeleev’s table

• Mendeleev predicted the ability of discovering new elements. So he left spaces in his table

• He corrected the wrong estimated atomic weights of some elements

• He had to make a disturbance in the ascending order of atomic weights for some elements, due to putting them in groups which suit their properties

• He also would have to deal with the isotopes of one element as different elements because they are different in their atomic weights.

Disadvantages of Mendeleev’s table

• Mendeleev predicted the ability of discovering new elements. So he left spaces in his table

• He corrected the wrong estimated atomic weights of some elements

• He had to make a disturbance in the ascending order of atomic weights for some elements, due to putting them in groups which suit their properties

• He also would have to deal with the isotopes of one element as different elements because they are different in their atomic weights.

.................. discovered that the nucleus of atom contains positively charged protons

• Moseley

• Rutherford

• Mendeleev

• Bohr

............... discovered the main energy levels

• Moseley

• Rutherford

• Mendeleev

• Bohr

1- Arranged ascendingly according to their atomic numbers

2- The way of filling the energy sublevels with electrons

• Modern periodic table

• Moseley’s periodic table

• Mendeleev’s table

• Rutherford

.............. are arranged ascendingly according to their atomic numbers

• Modern periodic table

• Moseley’s periodic table

• Mendeleev’s table

• Rutherford

s block .............

• has 2 groups

• Found in left side of periodic table

• has 6 groups

• Found in right side of periodic table