Atomic Structure
Competition questions
23 marksThe letters X, Y and Z represent different atoms.
3717X 3718Y 3818Z
Which statement is correct?
Source: 2024 CHIJ O Prelim P1 Q5
Which ion has fewer electrons than neutrons and fewer neutrons than protons?
| ion | neutrons | nucleons |
|---|---|---|
| W− | 18 | 37 |
| X2+ | 17 | 34 |
| Y3+ | 16 | 33 |
| Z3− | 16 | 31 |
Source: 2020 VJC J2 Prelim P1 Q2
What do the ions 18O2− and 19F− have in common?
Source: 2024 RI J2 Prelim P1 Q3
Beams of charged particles are deflected by an electric field. Under identical conditions, the angle of deflection of a particle is proportional to its charge/mass ratio. In an experiment, protons are deflected by an angle of +15° by an electric field. In another experiment under identical conditions, particle Y is deflected by an angle of −5°. What could be the composition of particle Y?
Source: 2022 DHS J2 Prelim P1 Q1
A sample of the element calcium was vaporised, ionised and passed through an electric field. It was observed that a beam of 40Ca2+ particles gave an angle of deflection of +4°. Assuming an identical set of experimental conditions, by what angle would a beam of 19F− particles be deflected?
Source: 2021 ACJC J2 Prelim P1 Q4
Which of the following species will produce the largest deflection when fired with equal velocity into an electric field?
Source: 2020 EJC J2 Prelim P1 Q1
X, Y and Z are isotopes of three different elements. An isotope of argon has a mass number of 41 and the same number of neutrons in the nucleus as each of the isotopes X, Y and Z. The species Ar, X+, Y2+ and Z3+ all contain the same number of electrons.
What are the mass numbers of X, Y and Z? Each option gives the mass numbers of X, Y and Z in that order.
2021 ACJC J2 Prelim P1 Q5
A stream of gaseous 168O2− ions was passed between two oppositely charged plates. Analysis of the deflection shows that these ions deflected at an angle of 10.0°. Under the same electric field, an unknown gaseous ion Z− is deflected at an angle of 2.58°. What is the isotopic mass of Z?
2021 TMJC J2 Prelim P1 Q2
In a particular experiment, a beam of 9Be2+ ions is deflected by an electric field through an angle of +10°. Which one of the following particles, when passed through the same electric field, will be deflected through an angle half the magnitude of 9Be2+?
| proton number | neutron number | electronic configuration | |
|---|---|---|---|
| A | 6 | 8 | 1s2 2s2 2p6 |
| B | 8 | 10 | 1s2 2s2 2p6 |
| C | 12 | 8 | 1s2 2s2 2p6 |
| D | 15 | 20 | 1s2 2s2 2p6 |
2020 VJC J1 Promo P1-P2 Q1
Scientists have discovered the use of an isotope of lead, Pb, which can treat non-cancerous eye disorders. 210Pb is an isotope of 207Pb. Which statement about these isotopes is correct?
2024 MSHS O Prelim P1 Q8
Which statement about the electrons in a ground state carbon atom is correct?
Source: 2020 YIJC J2 Prelim P1 Q1
The shape of each p orbital is represented as two lobes. How many electrons does Cu have in orbitals with four lobes?
Source: 2021 RI J2 Prelim P1 Q1
The shape of each p orbital is represented as two lobes. How many 3d orbitals have four lobes?
2022 ACJC J2 Prelim P1 Q2
An ion X2+ contains 24 protons. What is the electronic configuration of X3+?
Source: 2021 ACJC J2 Prelim P1 Q3
Which particle contains the most number of unpaired electrons?
Source: 2020 VJC J2 Prelim P1 Q1
A cation G2+ is isoelectronic with PH3. What is the ground state electronic configuration of G?
Source: 2017 RI J1 Promo P1-P3 Q2
Which electronic configuration represents an atom of an element, at ground state, that forms a stable ion with a charge of +3?
Source: 2021 EJC J2 Prelim P1 Q1
Which of the following about calcium and copper is correct?
Source: 2025 EJC J2 Prelim P1 Q2
There are occupancies of another type of subshell, beyond the s, p, d and f. This would be a g subshell, which is predicted to be found in the 5th shell of an atom, that is, the 5g subshell.
How many electrons in the 5g subshell would the element of atomic number 122 be expected to have?
Source: SJChO Mock 3 P1 Q12
Element Z, nucleon number 31, forms an ion Z3−. Where is Z found in the Periodic Table?
2024 SKSS O Prelim P1 Q6
The successive ionisation energies of the gaseous ion G+ are given in the table.
| number of electrons removed | 1 | 2 | 3 | 4 | 5 | 6 |
|---|---|---|---|---|---|---|
| ionisation energy / kJ mol−1 | 1907 | 2914 | 4964 | 6274 | 21 267 | 25 431 |
Which group in the Periodic Table does G belong to?
Source: 2021 HCI J2 Prelim P1 Q1
The table shows the fifth, sixth, seventh, eighth and ninth ionisation energies of an element in the third period.
| 5th | 6th | 7th | 8th | 9th | |
|---|---|---|---|---|---|
| ionisation energy / kJ mol−1 | 6270 | 21 270 | 25 430 | 29 870 | 35 920 |
Which element has these ionisation energy values?
Source: 2022 YIJC J2 Prelim P1 Q1
Which of the following statements best explains why the first ionisation energy of argon is higher than that of sulfur?
Source: 2020 ACJC J2 Prelim P1 Q5
