In the table below, some of the elements of the periodic table with atomic numbers from 3 to 18 are given. These are represented by letters, which are not the usual symbols of the elements. [5 MARKS]
3 4 5 6 7 8 9 10 A E G 11 12 13 14 15 16 17 18 B C D F
1. Which of these is a noble gas?
2. Which of these is a halogen?
3. Which of these is an alkali metal?
4. Which of these is an element with valency 4?
5. If A combines with F, what would be the formula of the resulting compound? What is the electronic arrangement of G?
In the table below, some of the elements of the periodic table with atomic numbers from 3 to 18 are given. These are represented by letters, which are not the usual symbols of the elements. [5 MARKS]
| 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 |
| A | E | G | |||||
| 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 |
| B | C | D | F |
1. Which of these is a noble gas?
2. Which of these is a halogen?
3. Which of these is an alkali metal?
4. Which of these is an element with valency 4?
5. If A combines with F, what would be the formula of the resulting compound? What is the electronic arrangement of G?
1. Atomic no. of G= 10, so its electronic configuration is 2,8. Its octet is complete. So, G is a noble gas.
2. Group- 17(valence electrons -7) is called Halogens as the elements in group 17 react with the metal to form salts. Atomic no. of F is 17, so its electronic configuration is 2,8,7. It has 7 valence electrons and reacts with the metal to form salts. Hence F is a halogen.
And Atomic number E is 9 so its electronic configuration is 2, 7. It has 7 valence electrons and reacts with the metal to form salts. Hence E is a halogen.
3. Group 1(valence electrons - 1) is called alkali metal as the elements of group 1 react with water to form alkali. Atomic no. of B is 11, so its electronic configuration is 2,8,1. It has 1 valence electron. Hence B is an alkali metal.
4. Atomic no. of D is 14, so its electronic configuration is 2,8,4. It has 4 valence electrons. Hence, D is an element with valency 4.
5. Atomic no. of A is 3, so its electronic configuration is 2,1.
Atomic no. of F is 17, so its electronic configuration is 2,8,7.
Both A and F have 1 valency.
So, If A combines with F, the formula of the resulting compound will be A+F−.
Atomic no. of G= 10, so its electronic configuration or arrangement is 2,8.
1. Atomic no. of G= 10, so its electronic configuration is 2,8. Its octet is complete. So, G is a noble gas.
2. Group- 17(valence electrons -7) is called Halogens as the elements in group 17 react with the metal to form salts. Atomic no. of F is 17, so its electronic configuration is 2,8,7. It has 7 valence electrons and reacts with the metal to form salts. Hence F is a halogen.
And Atomic number E is 9 so its electronic configuration is 2, 7. It has 7 valence electrons and reacts with the metal to form salts. Hence E is a halogen.
3. Group 1(valence electrons - 1) is called alkali metal as the elements of group 1 react with water to form alkali. Atomic no. of B is 11, so its electronic configuration is 2,8,1. It has 1 valence electron. Hence B is an alkali metal.
4. Atomic no. of D is 14, so its electronic configuration is 2,8,4. It has 4 valence electrons. Hence, D is an element with valency 4.
5. Atomic no. of A is 3, so its electronic configuration is 2,1.
Atomic no. of F is 17, so its electronic configuration is 2,8,7.
Both A and F have 1 valency.
So, If A combines with F, the formula of the resulting compound will be A+F−.
Atomic no. of G= 10, so its electronic configuration or arrangement is 2,8.
