Chemistry
In group I of the Periodic Table, three elements X, Y and Z have ionic radii 1.33 Å, 0.95 Å and 0.60 Å respectively. Giving a reason, arrange them in the order of increasing atomic numbers in the group.
Related Questions
Name the element which has :
(i) Two shells, both of which are completely filled with electrons ?
(ii) The electronic configuration 2, 8, 3 ?
(iii) A total of three shells with five electrons in its valence shell ?
(iv) A total of four shells with two electrons in its valence shell ?
(v) Twice as many electrons in its second shell as in its first shell ?
An element Barium has atomic number 56. Look up its position in the Periodic Table and answer the following questions.
(i) Is it a metal or a non-metal ?
(ii) Is it more or less reactive than calcium ?
(iii) What is its valency ?
(iv) What will be the formula of its phosphate ?
(v) Is it larger or smaller than caesium (Cs) in size ?
Explain why are the following statements not correct:
(i) All groups contain metals and non-metals.
(ii) Atoms of elements in the same group have the same number of electron(s).
(iii) Non-metallic character decreases across a period with increase in atomic number.
(iv) Reactivity increases with atomic number in a group as well as in a period.
State the number of elements in Period 1, Period 2, and Period 3 of the periodic table. Name them.