Question

(a) In this crossword puzzle (figure), the names of 11 elements are hidden. Symbols of these elements are given below. Complete the puzzle.
(1) $Cl$ (2) $H$ (3) $Ar$ (4) $O$ (5) $Xe$ (6) $N$ (7) $He$ (8) $F$ (9) $Kr$ (10) $Rn$ (11) $Ne$
(b) Identify the total number of inert gases, their names and symbols from the crossword puzzle.

Answer 1

Hint: The answer is based on the elemental symbols given in the periodic table and the arrangement of these elements in the periodic table based on their atomic number and also several properties.

Complete step – by – step answer:
In the previous classes, we have dealt with the topic which tells about the basic periodic table in which the elements are arranged accordingly.
Let us now work on filling the crossword puzzle.
- We are familiar with the modern periodic table and the arrangements of elements on the basis of atomic number.
- Periodic table consists of the elements arranged in the two forms that are groups that are arranged in columns and periods that are arranged in rows.
- To start with, we shall see the symbols given for the elements and abbreviate it one by one so that we can fill the crossword.
a)
(1) $Cl$ is the symbol given for the element Chlorine having the atomic number 17 and this can be filled in the column which is numbered 1.
(2) $H$ is the symbol used for the element hydrogen having the atomic number 1 and this is written in row number 2.
(3) $Ar$ is the symbol used for the element named argon which is an inert gas with the atomic number 18 and is written in row number 3.
(4) $O$ is the symbol used for an element named oxygen having atomic number 8 and is written in row number 4.
(5) $Xe$ is the symbol used for the element named xenon with atomic number 54 and is written in column 5 which is an inert gas.
(6) $N$ is the symbol used for the element named nitrogen with atomic number 7 and is written in row 6.
(7) $He$ is the symbol used for the element named Helium with atomic number 2 and is written in column 7 which is an inert gas.
(8) $F$ is the symbol used for the element named Fluorine with atomic number 9 and is written in column 8.
(9) $Kr$ is the symbol used for the element named Krypton with atomic number 36 and is written in row 9 which is the inert gas.
(10) $Rn$ is the symbol used for the element named Radium with atomic number 86 and is written in row 10 which is the inert gas.
(11) $Ne$ is the symbol used for the element named Neon with atomic number 10 and is written in column 11 which is the inert gas.

b) Now, among these elements, six of them are inert gases and hence a total number of inert gases are six in number which is marked grey.

Note: Note that the inert gases are those which are having the zero valencies and they are also called the noble gases. They are inert because they hold 8 valence electrons that are the octet configuration.