Which of the following statement is incorrect statement about the trend when going from left to right across the periods of modern periodic table?
Which of the following statement is incorrect statement about the trend when going from left to right across the periods of modern periodic table?
The correct option is B The atoms lose their electrons more easily
Modern periodic table
Modern periodic table arranges electrons in the increasing order of their atomic number. It divides the elements into 7 periods and 18 groups with the elements of the same group having same number of valence electrons and thereby similar properties. The elements of the same period have same of the energy levels or shells and the distinguishing electron enters the same shell.
Explanations for wrong answers
(A) Elements are arranged in the increasing order of atomic number in the periodic table. Therefore, across the period, the atomic number increases which is the number of electrons and protons in the atom. The electrons are added to the same shell across a period which is the outer shell of the atom. Since valence electrons are the number of electrons in outer shell, it increases across a period. Therefore, option (A) is incorrect.
(C) The oxides of elements at the right side of periodic table react with hydroxide ions when mixed with water releasing the protons of water. Therefore, solutions of oxides are acidic. Since the oxides react with basic hydroxides, the oxides must have an acidic character. Therefore, option (C) is incorrect.
(D) The ease of removal of electron is described by its metallic character. Across a period, the effective nuclear charge increases and therefore, the ease with which an electron can be removed also decreases. Therefore, metallic character decreases across a period. Option (D) is incorrect.
Explanation for correct answer
(B) Across a period, electrons are added to same shell. Therefore, the effect of increase in nuclear charge outweighs the effect in addition of negative charge. Therefore, the effective nuclear charge on the valence electron increases or the electrons are held more tightly towards the nucleus. This makes the removal of electrons more difficult. Therefore, the ease of removal of electrons decreases across a period.
The correct option is (B) The atoms lose their electrons more easily
The atoms lose their electrons more easily
Modern periodic table
Modern periodic table arranges electrons in the increasing order of their atomic number. It divides the elements into 7 periods and 18 groups with the elements of the same group having same number of valence electrons and thereby similar properties. The elements of the same period have same of the energy levels or shells and the distinguishing electron enters the same shell.
Explanations for wrong answers
(A) Elements are arranged in the increasing order of atomic number in the periodic table. Therefore, across the period, the atomic number increases which is the number of electrons and protons in the atom. The electrons are added to the same shell across a period which is the outer shell of the atom. Since valence electrons are the number of electrons in outer shell, it increases across a period. Therefore, option (A) is incorrect.
(C) The oxides of elements at the right side of periodic table react with hydroxide ions when mixed with water releasing the protons of water. Therefore, solutions of oxides are acidic. Since the oxides react with basic hydroxides, the oxides must have an acidic character. Therefore, option (C) is incorrect.
(D) The ease of removal of electron is described by its metallic character. Across a period, the effective nuclear charge increases and therefore, the ease with which an electron can be removed also decreases. Therefore, metallic character decreases across a period. Option (D) is incorrect.
Explanation for correct answer
(B) Across a period, electrons are added to same shell. Therefore, the effect of increase in nuclear charge outweighs the effect in addition of negative charge. Therefore, the effective nuclear charge on the valence electron increases or the electrons are held more tightly towards the nucleus. This makes the removal of electrons more difficult. Therefore, the ease of removal of electrons decreases across a period.
The correct option is (B) The atoms lose their electrons more easily
