(a) How does the atomic size vary on going down from top to bottom in a group of the periodic table? Why does it vary this way?
(b) Lithium, sodium and potassium are all metals that react with water to liberate hydrogen gas. Is there any similarity in the atoms of these elements? Explain your answer.
(a) The atomic size increases on going down the group of the periodic table as on moving top to the bottom, shells are added at each step due to this the size of the atom increases.
(b) Yes, the atoms of all the three elements lithium, sodium, and potassium have one electron in their outermost shells. Therefore, they react with water to liberate hydrogen gas.
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- (a) Lithium, sodium, potassium are all metals that react with water to liberate hydrogen gas. Is there any similarity in the atoms of these elements?(b) Helium is an unreactive gas and neon is a gas of extremely low reactivity. What, if anything, do their atoms have in common?
- (a) How does the chemical reactivity of alkali metals vary on going down in group 1 of the periodic table?(b) How does the chemical reactivity of the halogens vary on going down in group 17 of the periodic table?
- How does the valency of elements vary in going down a group of the periodic table?
- (a) How does the size of atoms (atomic size) generally vary in going from left to right in a period of the periodic table? Why does it vary this way?(b) What happens to the metallic character of the elements as we move from left to right in a period of the periodic table?
- (a) List any three observations which posed a challenge to Mendeleev’s Periodic law.(b) How does the metallic character of elements vary on moving from(i) left to right in a period,(ii) from top to bottom in a group of the Modem Periodic Table?Give a reason for your answer.
- (a) How does the tendency to lose electrons change as we go down in group 1 of the periodic table? Why does it change this way?(b) How does the tendency to gain electrons change as we go down in group 17 of the periodic table? Why does it change this way?
- (a) How does the electropositive character of elements change on going down in a group of the periodic table?(b) State how the valency of elements varies (i) in a group, and (ii) in a period, of the periodic table.
- Generally, metals react with acids to give salt and hydrogen gas. Which of the following acids does not give hydrogen gas on reacting with metals (except Mn and Mg)?H2SO4HClHNO3All of these
- (a)Explain why, metals usually do not liberate hydrogen gas with dilute nitric acid.(b)Name two metals which can, however, liberate hydrogen gas from very dilute nitric acid.
- How does the number of valence electrons vary on moving from left to right:(i) In the first period of the periodic table? (ii) In the second period of the periodic table?
- Does sodium react with water?
- Metals generally react with dilute acids to produce hydrogen gas. Which one of the following metals does not react with dilute hydrochloric acid?MagnesiumAluminiumIronCopper
- (a) What is the usual number of valence electrons and valency of group 18 elements of the periodic table?(b) What happens to the number of valence electrons in the atoms of elements as we go down in a group of the periodic table?
- (a) What is a group in the periodic table? In which part of a group would you separately expect the elements to have (i) the greatest metallic character (ii) the largest atomic size?(b) In what respects do the properties of group 1 elements differ from those of group 17 elements? Explain with examples by taking one element from each group. (c) From the standpoint of atomic structure, what determines which element will be the first and which the last in a period of the periodic table? (d) Explain why, the properties of elements are repeated after 2, 8, 18, and 32 elements in the periodic table. (e) What are the advantages of the periodic table?
- (a)In the modern Periodic Table, why does cobalt with higher atomic mass of 58.93 appear before nickel having lower atomic mass of 58.71?(b) Why could no fixed position be given to hydrogen in Mendeleev’s periodic table?
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