GENERAL KNOWLEDGE

Detailed explanation-1: -In the modern periodic table, the elements are arranged according to their atomic number-not their relative atomic mass . In the periodic table the elements are arranged into: rows, called periods, in order of increasing atomic number. vertical columns, called groups, where the elements have similar properties.

Detailed explanation-2: -In the modern periodic table, the elements are listed in order of increasing atomic number. The atomic number is the number of protons in the nucleus of an atom.

Detailed explanation-3: -The modern table is based on Mendeleev’s table, except the modern table arranges the elements by increasing atomic number instead of atomic mass. Atomic number is the number of protons in an atom, and this number is unique for each element.

Detailed explanation-4: -A modern periodic table arranges the elements in increasing order of their atomic numbers and groups atoms with similar properties in the same vertical column (Figure 3.2. 2). Each box represents an element and contains its atomic number, symbol, average atomic mass, and (sometimes) name.

Detailed explanation-5: -The number of electrons in an element is fixed. No two elements can have the same atomic number. Hence, elements can be easily classified in the increasing order of their atomic numbers.