Which of the following is smallest in size-
Which of the following is smallest in size-
The correct option is C F-
Atomic radius:
Atomic radius is the distance from the center of an atom to the outermost shell of the electron. When an atom gains an electron, The number of electrons in the atom will be relatively higher than the number of protons. Therefore, the effective nuclear charge of the atom decreases and the size of the atom increases. Ions obtained by addition of electrons are called anions and anions will always have greater size than its corresponding atom.
Explanation:
Species that have the same number of electrons in the atoms are called isoelectronic species. The atomic number of a neutral element is equal to the number of electrons in it. The atomic number of Carbon (C), Nitrogen (N), Oxygen (O) and fluorine (F) are 6, 7, 8 and 9 respectively. The magnitude of charge represents the number of electrons added to the atom and therefore, the given four ionic species are isoelectronic with 10 electrons.
The ionic size of isoelectronic species is inversely proportional to its atomic number because nuclear charge increases with atomic number. Therefore, across the period, the size of the ion decreases due to an increase in effective nuclear charge.
Explanation for correct answer
Fluorine has the highest atomic number and therefore, it will the smallest ion.
Hence, option c) is the correct answer.
Explanations for wrong answer
Option a) is incorrect because the atomic number of oxygen is less than that of fluorine.
Option b) is incorrect as the atomic number of carbon is the lowest and therefore, its ion will have the largest size.
Option d) is incorrect because nitrogen has an atomic number lower than Oxygen and Fluorine.
F-
Atomic radius:
Atomic radius is the distance from the center of an atom to the outermost shell of the electron. When an atom gains an electron, The number of electrons in the atom will be relatively higher than the number of protons. Therefore, the effective nuclear charge of the atom decreases and the size of the atom increases. Ions obtained by addition of electrons are called anions and anions will always have greater size than its corresponding atom.
Explanation:
Species that have the same number of electrons in the atoms are called isoelectronic species. The atomic number of a neutral element is equal to the number of electrons in it. The atomic number of Carbon (C), Nitrogen (N), Oxygen (O) and fluorine (F) are 6, 7, 8 and 9 respectively. The magnitude of charge represents the number of electrons added to the atom and therefore, the given four ionic species are isoelectronic with 10 electrons.
The ionic size of isoelectronic species is inversely proportional to its atomic number because nuclear charge increases with atomic number. Therefore, across the period, the size of the ion decreases due to an increase in effective nuclear charge.
Explanation for correct answer
Fluorine has the highest atomic number and therefore, it will the smallest ion.
Hence, option c) is the correct answer.
Explanations for wrong answer
Option a) is incorrect because the atomic number of oxygen is less than that of fluorine.
Option b) is incorrect as the atomic number of carbon is the lowest and therefore, its ion will have the largest size.
Option d) is incorrect because nitrogen has an atomic number lower than Oxygen and Fluorine.
