NST2601
ASSIGNMENT 2
ANSWERS 2026
NST2601 ASSIGNMENT 2 ANSWERS
2026
,NST2601 ASSESSMENT 02
ASSIGNMENT DUE DATE: 05 June 2026
Question 1
1.1 A particle in physical science is a small localized unit of matter or energy with
definable properties (mass, charge, position) that can interact with other objects.
1.2 The electron.
1.3 John Dalton.
1.4 0 (neutron is electrically neutral).
1.5 8 electrons.
1.6 Bohr model (planetary model) with fixed energy level orbits.
1.7 Proton: symbol p (often written as p⁺ for a positively charged proton).
1.8 Chlorine has atomic number 17.
1.9 Isotopes.
1.10 The nucleus.
Question 2
, 2.1 Cathode rays bend toward a positively charged plate because they are
composed of electrons (negatively charged); the electric field exerts a force F = qE
with q negative, pulling them toward the positive plate.
2.2 In Rutherford’s gold foil experiment, most alpha particles passed through the foil,
but a few were deflected at large angles. This indicated a very small, dense,
positively charged nucleus, contradicting the plum pudding model’s diffuse positive
charge and leading to the nuclear model of the atom.
2.3 Electron configuration is the arrangement of electrons in an atom across energy
levels and subshells, describing how electrons occupy orbitals to minimize energy
(e.g., 1s² 2s² 2p⁶).
2.4 In a neutral atom, the number of electrons equals the atomic number (Z).
2.5 Isotopes have similar chemical properties because they have the same electron
configuration and hence similar bonding behavior, despite different neutron numbers.
2.6 Protons are positively charged and located in the nucleus; electrons are
negatively charged and located in the electron cloud around the nucleus.
2.7 Valence electrons are the electrons in the outermost shell (or subshell) that
participate in bonding and determine most of an element’s chemical properties and
reactivity.
2.8 Paired electrons are less stable than unpaired electrons in an orbital because
electron–electron repulsion increases energy when two electrons occupy the same
orbital; Hund’s rule favors unpaired electrons in separate orbitals to lower energy.
2.9 s-orbitals are spherical and exist in every principal energy level; p-orbitals are
dumbbell-shaped, come in sets of three (px, py, pz), and begin in the second energy
level.
2.10 Carbon dating is used to estimate the age of organic materials (e.g., wooden
artifacts, bone, charcoal) by measuring the remaining ratio of carbon-14 to carbon-
12; it relies on the 14C dating half-life (~5730 years).
ASSIGNMENT 2
ANSWERS 2026
NST2601 ASSIGNMENT 2 ANSWERS
2026
,NST2601 ASSESSMENT 02
ASSIGNMENT DUE DATE: 05 June 2026
Question 1
1.1 A particle in physical science is a small localized unit of matter or energy with
definable properties (mass, charge, position) that can interact with other objects.
1.2 The electron.
1.3 John Dalton.
1.4 0 (neutron is electrically neutral).
1.5 8 electrons.
1.6 Bohr model (planetary model) with fixed energy level orbits.
1.7 Proton: symbol p (often written as p⁺ for a positively charged proton).
1.8 Chlorine has atomic number 17.
1.9 Isotopes.
1.10 The nucleus.
Question 2
, 2.1 Cathode rays bend toward a positively charged plate because they are
composed of electrons (negatively charged); the electric field exerts a force F = qE
with q negative, pulling them toward the positive plate.
2.2 In Rutherford’s gold foil experiment, most alpha particles passed through the foil,
but a few were deflected at large angles. This indicated a very small, dense,
positively charged nucleus, contradicting the plum pudding model’s diffuse positive
charge and leading to the nuclear model of the atom.
2.3 Electron configuration is the arrangement of electrons in an atom across energy
levels and subshells, describing how electrons occupy orbitals to minimize energy
(e.g., 1s² 2s² 2p⁶).
2.4 In a neutral atom, the number of electrons equals the atomic number (Z).
2.5 Isotopes have similar chemical properties because they have the same electron
configuration and hence similar bonding behavior, despite different neutron numbers.
2.6 Protons are positively charged and located in the nucleus; electrons are
negatively charged and located in the electron cloud around the nucleus.
2.7 Valence electrons are the electrons in the outermost shell (or subshell) that
participate in bonding and determine most of an element’s chemical properties and
reactivity.
2.8 Paired electrons are less stable than unpaired electrons in an orbital because
electron–electron repulsion increases energy when two electrons occupy the same
orbital; Hund’s rule favors unpaired electrons in separate orbitals to lower energy.
2.9 s-orbitals are spherical and exist in every principal energy level; p-orbitals are
dumbbell-shaped, come in sets of three (px, py, pz), and begin in the second energy
level.
2.10 Carbon dating is used to estimate the age of organic materials (e.g., wooden
artifacts, bone, charcoal) by measuring the remaining ratio of carbon-14 to carbon-
12; it relies on the 14C dating half-life (~5730 years).
