In the periodic table generally following similarity is found in elements of same group.
Atomic number
Number of electrons in outermost orbit of an atom
Number of isotopes
Atomic volume
In the periodic table generally following similarity is found in elements of same group.
Atomic number
Number of electrons in outermost orbit of an atom
Number of isotopes
Atomic volume
The correct option is B Number of electrons in outermost orbit of an atom
Groups in periodic table
Periodic table arranges metals in the increasing order of atomic number. The periodic table is divided into 7 periods and 18 groups such that the elements with similar physical and chemical properties are in the same group. The vertical columns in the periodic table are called groups. The groups in the periodic table include alkali metals (Group 1), alkaline earth metals (Group 2), halogens (Group 17) among the others.
Explanation for the wrong answers
(A) No two elements in the periodic table have same atomic number. The elements with same atomic number and different masses are called isotopes of the element and are not included in the periodic table. Therefore, option (A) is incorrect.
(C) Isotopes are species with same atomic number with different atomic mass. The number of isotopes of elements of same group are not same. Therefore, option (C) is incorrect.
(D) The atomic volume depends on the mass of the atom. Since the elements of the same group have different masses, the atomic volume will be different. Therefore, option (D) is incorrect.
Explanations for the correct answer
(B) The chemical properties of the elements of a group are similar. The chemical properties of the element depend on the number of electrons lost or gained by the atom during a reaction. Therefore, it depends on the number of electrons in the valence shell of atom. The elements of a group have same number of electrons in the valence shell. They differ in the number of filled inner shells present in the atom. For example, both Lithium (Li) and Sodium (Na) contain one electron in the outermost electron shell.
The correct option is (B) Number of electrons in outermost orbit of an atom
Number of electrons in outermost orbit of an atom
Groups in periodic table
Periodic table arranges metals in the increasing order of atomic number. The periodic table is divided into 7 periods and 18 groups such that the elements with similar physical and chemical properties are in the same group. The vertical columns in the periodic table are called groups. The groups in the periodic table include alkali metals (Group 1), alkaline earth metals (Group 2), halogens (Group 17) among the others.
Explanation for the wrong answers
(A) No two elements in the periodic table have same atomic number. The elements with same atomic number and different masses are called isotopes of the element and are not included in the periodic table. Therefore, option (A) is incorrect.
(C) Isotopes are species with same atomic number with different atomic mass. The number of isotopes of elements of same group are not same. Therefore, option (C) is incorrect.
(D) The atomic volume depends on the mass of the atom. Since the elements of the same group have different masses, the atomic volume will be different. Therefore, option (D) is incorrect.
Explanations for the correct answer
(B) The chemical properties of the elements of a group are similar. The chemical properties of the element depend on the number of electrons lost or gained by the atom during a reaction. Therefore, it depends on the number of electrons in the valence shell of atom. The elements of a group have same number of electrons in the valence shell. They differ in the number of filled inner shells present in the atom. For example, both Lithium (Li) and Sodium (Na) contain one electron in the outermost electron shell.
The correct option is (B) Number of electrons in outermost orbit of an atom
