A research balloon samples high-altitude air where atoms can be ionised by radiation from space. Fig. 1 shows an oxygen atom before and after it gains two e...
Question 1 Report
A research balloon samples high-altitude air where atoms can be ionised by radiation from space. Fig. 1 shows an oxygen atom before and after it gains two electrons. The charged oxygen ion can affect instruments that measure electrical current in the thin air. Each diagram gives the number of protons, and the shells show the electron arrangement. The balloon team needs to calculate the charge correctly before calibrating its detector.
(a) Calculate the charge on the oxygen ion. [1]
(b) What is the formula of this ion? [1]
(c) Which particles have moved into the oxygen atom? [1]
(d) Describe why the ion has a different charge from the atom. [2]
(e) Give the number of protons in the oxygen ion. [1]
Answer Details
(a) The oxygen ion has 8 protons but, after gaining two electrons, 10 electrons. It has two extra negative charges, so its charge is \(-2\). [1]
(b) The formula is \(\mathrm{O^{2-}}\). [1]
(c) The particles that moved into the atom are electrons. [1]
(d) The ion has gained two electrons. It therefore has two more electrons than protons, giving an overall negative charge. [2]
(e) Ion formation changes electrons, not the nucleus. The oxygen ion still has 8 protons. [1]
Download The App On Google Playstore
Everything you need to excel in your exams
