The wave number of the first line of Balmer series of hydrogen is 15200 cm -1. The wave number of the first Balmer line of Li 2+ ion is

Question

The wave number of the first line of Balmer series of hydrogen is 15200 cm -1. The wave number of the first Balmer line of Li 2+ ion is (A) 15200 cm -1 (B) 60800 cm -1 (C) 76000 cm -1 (D) 136800 cm -1

Tardigrade Admin · Accepted Answer

barv H 2⊕=R((1/n12)-(1/n22))=15200 cm -1 barv Li 2+=R Z2((1/n12)-(1/n22))=32 × 15200 =136800 cm -1

Q. The wave number of the first line of Balmer series of hydrogen is $15200 c m^{- 1}$ . The wave number of the first Balmer line of $L i^{2 +}$ ion is

$15200 c m^{- 1}$

$60800 c m^{- 1}$

$76000 c m^{- 1}$

$136800 c m^{- 1}$

$\overset{v}{ˉ}_{H_{2}}^{\oplus} = R (\frac{1}{n _{1}^{2}} - \frac{1}{n _{2}^{2}}) = 15200 c m^{- 1}$
$\overset{v}{ˉ}_{L i^{2 +}} = R Z^{2} (\frac{1}{n _{1}^{2}} - \frac{1}{n _{2}^{2}}) = 3^{2} \times 15200$
$= 136800 c m^{- 1}$

Q. The wave number of the first line of Balmer series of hydrogen is 15200cm−1. The wave number of the first Balmer line of Li2+ ion is

15200cm−1

60800cm−1

76000cm−1

136800cm−1