Find the following information for the elements shown in Fig. Class 9

Find the following information for the elements shown in Fig. Class 9

Question 1.

Find the following information for the elements shown in Fig. Class 9

1. Name of the element
2. Symbol
3. Total number of electrons
4. Number of valence electrons
5. Valency of the element
6. Number of protons
7. Atomic number

Answer:

(a): 1 shell with 2 electrons

(b): 2 shells K= 2, L = 8

(c) Atom with K = 2, L = 8, M = 5 (with an extra electron shown, total =15)

(d): 2 shells - K = 2, L = 7

(a) Atom with 2 electrons (K = 2):

1. Name: Helium
2. Symbol: He
3. Total number of electrons: 2
4. Number of valence electrons: 2 (only shell is K-shell)
5. Valency: 0 (outermost shell is completely filled with 2 electrons, which is the maximum for K-shell - stable)
6. Number of protons: 2
7. Atomic number: 2

(b) Atom with K = 2, L = 8 - total 10 electrons:

1. Name: Neon
2. Symbol: Ne
3. Total number of electrons: 10
4. Number of valence electrons: 8 (L-shell is the outermost shell)
5. Valency: 0 (outermost shell has 8 electrons - complete octet, stable)
6. Number of protons: 10
7. Atomic number: 10

(c) Atom with K = 2, L = 8, M = 5 (with an extra electron shown, total = 15)

1. Name: Phosphorus
2. Symbol: P
3. Total number of electrons: 15
4. Number of valence electrons: 5 (M-shell is the outermost shell)
5. Valency: 3 (needs to gain 3 electrons to complete octet; since 5 > 4, it tends to gain electrons: 8-5 = 3)
6. Number of protons: 15
7. Atomic number: 15

(d) Atom with K = 2, L = 7 - total 9 electrons:

1. Name: Fluorine
2. Symbol: F
3. Total number of electrons: 9
4. Number of valence electrons: 7 (L-shell is the outermost shell)
5. Valency: 1 (needs to gain 1 electron to complete octet: 8 - 7 = 1)
6. Number of protons: 9
7. Atomic number: 9