(a) How were the positions of isotopes of an element decided in the modern periodic table ?
(b) How were the positions of cobalt and nickel resolved in the modern periodic table ?
(c) Where should hydrogen be placed in the modern periodic table ? Give reason for your answer.
(a) How were the positions of isotopes of an element decided in the modern periodic table ?
(b) How were the positions of cobalt and nickel resolved in the modern periodic table ?
(c) Where should hydrogen be placed in the modern periodic table ? Give reason for your answer.
(a) Modern periodic table is based on atomic numbers. So, the position of isotopesof elements was decided by arranging the elements in ascending order of their atomic numbers. As isotopes have the same atomic number they do not need to be given different slots. Thus they are placed in same slot.
(b)According to modern periodic law, elements are arranged in the order of increasing atomic numbers. So, in the modern periodic table, cobalt with lower atomic number (27) comes first and nickel with higher atomic number (28) comes later, even if their atomic masses are in the wrong order.
(c)The modern periodic table is based on the atomic numbers of the elements and also upon their electronic distribution. Alkali metals as well as hydrogen have one electron in their valence shell. Therefore, hydrogen should be placed in the group of alkali metals. However, it has been assigned a separate position and is not a member of the group of alkali metals since it is a non-metal.
(a) Modern periodic table is based on atomic numbers. So, the position of isotopesof elements was decided by arranging the elements in ascending order of their atomic numbers. As isotopes have the same atomic number they do not need to be given different slots. Thus they are placed in same slot.
(b)According to modern periodic law, elements are arranged in the order of increasing atomic numbers. So, in the modern periodic table, cobalt with lower atomic number (27) comes first and nickel with higher atomic number (28) comes later, even if their atomic masses are in the wrong order.
(c)The modern periodic table is based on the atomic numbers of the elements and also upon their electronic distribution. Alkali metals as well as hydrogen have one electron in their valence shell. Therefore, hydrogen should be placed in the group of alkali metals. However, it has been assigned a separate position and is not a member of the group of alkali metals since it is a non-metal.
