(a) How does metallic character of elements in Modern Periodic Table vary on moving from
(i) left to right in a period?
(ii) top to bottom in a group?
Explain with the help of an example in each case.
(b) If an element X is placed in group 14, what will be the nature of bond in its chloride? Write the chemical formula of the compound formed.
(c) An element X has mass number = 35 and number of neutrons = 18. What is the atomic number of X? Write electronic configuration of X and determine its valency.
Answers
Answer:
(a)(i) when you go left to right then increase the character of non metallic
(c) Z=17, electronic configuration:-2,8,7 & its valency:-1
Period Table and metallic properties
Explanation:
A) When you move from left to right on the period table, the metallic characteristic decreases. This occurs as atoms more readily accept electrons to fill a valence shell than lose them to remove the unfilled shell.
Example: Na (Sodium) is more metallic than Zn (Zinc).
Metallic character increases as you move down an element group in the periodic table. This is because electrons become easier to lose as the atomic radius increases, where there is less attraction between the nucleus and the valence electrons because of the increased distance between them.
Example: K (Potassium) is more metallic than Li (Lithium).
B) Element X is placed in group 14, so it will have 4 valence electrons. So it will form chloride with chemical formula XCl4 and it will form covalent bonds.
C) Element X has mass number = 35 and number of neutrons = 18.
Atomic number = mass number - neutrons = 35 - 18 = 17.
Electron configuration is 1s2 / 2s2 2p6 / 3s2 3p5
Number of electrons on the outer shell is 7, so chlorine needs to accept 1 electron to become stable. Valency of element X is 1.
Please refer to the picture for the electronic configuration in the correct format.
