iGCSE Physics (0625) 5.1.1 The Atom-Exam Style Questions- New Syllabus
▶️ Answer/Explanation
Detailed solution:
A neutral atom has an equal number of protons (charge $+1$) and electrons (charge $-1$).
A negatively charged ion has an excess of electrons compared to protons.
To return to a neutral state, the ion must remove this excess negative charge.
Since the number of protons defines the element and remains constant in chemical changes, only electrons are transferred.
Therefore, the loss of electrons reduces the negative charge until it equals the positive nuclear charge.
This transition results in a neutral oxygen atom, making option C the correct choice.
▶️ Answer/Explanation
Detailed solution:
An atom consists of a central nucleus containing protons (charge +1) and neutrons (charge 0).
Since protons are positive and neutrons are neutral, the nucleus has an overall positive charge.
Electrons, which carry a negative charge of −1, orbit this nucleus in specific energy levels.
The electrostatic attraction between the positive nucleus and negative electrons keeps the atom together.
Therefore, the correct structural description is negatively charged electrons surrounding a positively charged nucleus.
This matches Option B, while other options incorrectly identify the charges of the subatomic components.
▶️ Answer/Explanation
Detailed solution:
An atom consists of a central nucleus containing protons and neutrons.
Protons carry a relative charge of $+1$, while neutrons have a charge of $0$, making the nucleus positively charged.
Electrons, which carry a relative charge of $-1$, move in orbits around this central nucleus.
Electrostatic attraction between the positive nucleus and negative electrons holds the atom together.
Therefore, the correct structural description is a positively charged nucleus surrounded by negatively charged electrons.
This corresponds exactly to the description provided in Option C.