Complete:

The most important attempts to classify elements are ……….,…… and

Mendeleev discovered that the properties of element were repeated ………… by the beginning of each .

 In 1913, the Newzeland scientist ……………. discovered that the

nucleus of the atom contains …………       

Moseley discovered after studying ……………. rays, the periodic properties of elements are related to their …………… and not to their ……………. 

The modern periodic table consists of ……………. horizontal periods and ……………. vertical groups

 Groups of d-block take letter …………. except group ………….which consists of ……………. vertical column.

 In the modern periodic table, element of group ……………… are located on the left, right side, while elements of group …………….are located in the middle of the table.

The number of electrons in the outer most energy level in the atom of an element indicates its ……………. number. 

Element 13X lies in period ……………. and group ……………. in the modern periodic table

By increasing the atomic number within a period, the atomic size……………. because the ……………. between positive nucleus and outer most electrons increases

The atomic size of Magnesium (12Mg) atom is ……………. than that of beryllium (4Be) atom as the ……………. of Magnesium atom is greater than that of beryllium atom.

……………. Is the ability of the atom in covalent molecule to attract the ……………. of the bond towards itself.

 By increasing the atomic size in the group, the electronegativity……………. and the atomic number …………….

Write the scientific term:

The first real periodic table for classifying elements

The partition of periodic table that contains elements having similar proportion in vertical column.

 The table in which elements are arranged according to their atomic number

A group of elements found of the periodic table and includes ten vertical columns.

Elements of d-block in the modern periodic table

 Elements of group zero in the modern periodic table.