Q24 of 30 Page 196

An element has electronic configuration 2, 8, 7.

(a) To which group and period of the long form of Periodic Table does it belong?


(b) What is atomic number of this element?


(c) Is it metallic or non-metallic and why?


(d) Identify the element.


(e) Name an element chemically similar to this element.

(a) Element belongs to 17 group and 3 period.

(b) Atomic number of this element is 17 because atomic number is equal to total electrons present in it.


(c) It is non-metallic because it has 7 electrons in its valence shell so it can gain only one electron to complete its octet.


(d) This element is Chlorine.


(e) Bromine is chemically similar to this element because bromine and chlorine are the elements of same group.


More from this chapter

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22

An element belongs to 4th period and group 17 of the periodic table. Find out:

(a) the number of valence electrons.


(b) is it a metal or non-metal.


(c) the name of the element.


(d) formula of its compound with hydrogen.


(e) electron dot structure of this element with calcium.

 23

The position of certain elements in the Periodic Table are shown below.


Using the above table answer the following questions:


(a) Which element will form only covalent compounds?


(b) Which element is a non-metal with valency 2?


(c) Which element is a metal with valency 2?


(d) Out of H, C, F, which has largest atomic size?


(e) Give name of family to which H, C and F belong?

 25

The positions of three elements A, B and C in the periodic table are indicated below:


(a) State whether element C would be a metal or a non-metal. Why?


(b) Which is the more active element, A or C? Why?


(c) Which type of ion (cation or anion) will be formed by the element C? Why?

 26

Atoms of seven elements A, B, C, D, E, F and g have a different number of electronic shells but have the same number of electrons in their outermost shells. The elements A and C combine with chlorine to form and acid and common salt respectively. The oxide of element A is liquid at room temperature and is a neutral substance, while the oxide of the remaining six elements are basic in nature. Based on the above information, answer the following question:

(i) What could the element A be?


(ii) Will element A to G belong to the same period or same group of the periodic table?


(iii) Write the formula of the compound formed by the reaction of the element A with oxygen.


(iv) Show the formation of the compound by a combination of element C with chlorine with the help of electronic structure.


(v) What would be the ratio of number of combining atoms in a compound formed by the combination of element A with carbon?


(vi) Which one of the given elements is likely to have the smallest atomic radius?