What is the electronic configuration (shell by shell) of the element O (atomic number 8)?
Answer and explanation
Correct answer: B. 2,6
- Step 1: Fill the shells in order: 2 in the first, 8 in the second, 8 in the third. Step 2. 8 electrons give 2,6. Answer: 2,6. Why not the others: 2,7 is what you get if you count one or two electrons too many or too few. 2,5 is what you get if you count one or two electrons too many or too few. 2,8 is what you get if you count one or two electrons too many or too few.
Practise more Physical and inorganic chemistry.
Free questions with an explanation for every one, and full timed JEE Advanced mock tests.
More Physical and inorganic chemistry questions
- 2 dm³ of a gas at 300 K is brought to 450 K at constant pressure. What is the new volume?
- How many water molecules are present in 0.5 mol of H₂O? (Avogadro constant = 6.02 × 10²³ per mol)
- The rate of a reaction is proportional to [A]^2. By what factor does the rate change if [A] is multiplied by 3?
- A first-order reaction has a rate constant of 0.0347 per min. What is its half-life? (ln 2 = 0.693)
- A current of 9.65 A is passed for 2000 s through a solution of a zinc salt, where each Zn ion gains 2 electrons. What mass of zinc is deposi…
- Given ΔHf(CO₂) = −394 kJ/mol, ΔHf(H₂O, liquid) = −286 kJ/mol and ΔHf(CH₄) = −75 kJ/mol, find the enthalpy of combustion of methane, CH₄ + 2O…