What is the energy (in J atom-1) required for the following process ? Li2+(g) → Li3+(g) + e- (Take the ionization energy for the H atom in the ground state as 2.18 x 10-18 J atom-1)

The correct answer is Option 3. Full mathematical solution steps and hints are accessible in the interactive StemCET workspace.

Chemistry Q52 – JEE-MAIN 2026

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Home Chemistry Structure of AtomQuestion #598

What is the energy (in J atom

^{- 1}

) required for the following process ? Li

^{2 +}

(g)

\to

^{3 +}

(g) + e

^{-}

(Take the ionization energy for the H atom in the ground state as

2.18 \times 10^{- 18}

J atom

^{- 1}

)

Clue 1 of 3: Identify the type of species

The process involves the ionization of a Li $^{2 +}$ ion, which is a hydrogen-like species (contains only one electron).

🧠 Full Solution Path

Step 1: Identify the Species and Process✦ Active

The given process is Li $^{2 +}$ (g) $\to$ Li $^{3 +}$ (g) + e $^{-}$ . This represents the removal of the last electron from a Li $^{2 +}$ ion. Lithium (Li) has an atomic number $Z = 3$ . A Li $^{2 +}$ ion has lost two electrons, leaving it with only one electron, making it a hydrogen-like species.

Step 2: Recall the Formula for Ionization Energy of Hydrogen-like Species○ Expand

For a hydrogen-like species, the ionization energy from the ground state ( $n = 1$ ) is directly proportional to the square of its atomic number ( $Z$ ). The formula is given by:

I E = I E_{H} \times Z^{2}

where $I E_{H}$ is the ionization energy of the hydrogen atom in its ground state.

Step 3: Calculate the Energy Required○ Expand

Given $I E_{H} = 2.18 \times 10^{- 18}$ J atom $^{- 1}$ and for Lithium, $Z = 3$ . Substitute these values into the formula:

I E_{L i^{2 +}} = (2.18 \times 10^{- 18} {J atom}^{- 1}) \times (3)^{2}

I E_{L i^{2 +}} = (2.18 \times 10^{- 18}) \times 9 {J atom}^{- 1}

I E_{L i^{2 +}} = 19.62 \times 10^{- 18} {J atom}^{- 1}

Converting to a standard scientific notation format:

I E_{L i^{2 +}} = 1.962 \times 10^{- 17} {J atom}^{- 1}

This value matches option 3.

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Chemistry Question 52 – JEE-MAIN 2026

Clue 1 of 3: Identify the type of species

🧠 Full Solution Path