Atomic Structure questions

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Atomic Structure question collection

Review Atomic Structure questions for Chemistry, with correct answers shown and coverage across protons, neutrons and electrons; atomic number and mass number; isotopes and relative atomic mass.

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Question 1

Which statement about atom structure is correct?
  1. Almost all the mass is concentrated in the nucleus
  2. Most of the mass is in electron shells
  3. Protons orbit around electrons
  4. Neutrons are negatively charged

Question 2

An atom has atomic number \(12\) and mass number \(24\). How many neutrons does it have?
  1. \(12\)
  2. \(24\)
  3. \(6\)
  4. \(36\)

Question 3

For chlorine isotopes \(35\) (\(75\%\)) and \(37\) (\(25\%\)), what is the relative atomic mass?
  1. \(35.5\)
  2. \(36.0\)
  3. \(35.0\)
  4. \(36.5\)

Question 4

What is the electronic structure of sodium (atomic number \(11\))?
  1. \(2,8,1\)
  2. \(2,8,2\)
  3. \(2,7,2\)
  4. \(2,9\)

Question 5

What is the electronic structure of calcium (atomic number \(20\))?
  1. \(2,8,8,2\)
  2. \(2,8,8,1\)
  3. \(2,8,10\)
  4. \(2,10,8\)

Question 6

What charge does a sodium ion have after losing one electron?
  1. \(+1\)
  2. \(-1\)
  3. \(+2\)
  4. \(0\)

Question 7

What is the electron arrangement of a chloride ion, Cl-?
  1. \(2,8,8\)
  2. \(2,8,7\)
  3. \(2,7,8\)
  4. \(2,8,8,1\)

Question 8

What is the approximate radius of an atom?
  1. \(1 \times 10^{-10}\,\mathrm{m}\)
  2. \(1 \times 10^{-6}\,\mathrm{m}\)
  3. \(1 \times 10^{-14}\,\mathrm{m}\)
  4. \(1 \times 10^{-2}\,\mathrm{m}\)

Question 9

What is the relative mass of an electron compared with a proton?
  1. Very small, about \(\frac{1}{1836}\)
  2. Exactly \(1\)
  3. About \(1836\)
  4. Exactly \(0\)

Question 10

How does Group 1 reactivity change down the group?
  1. It increases
  2. It decreases
  3. It stays constant
  4. It alternates every element

Question 11

How does Group 7 reactivity change down the group?
  1. It decreases
  2. It increases
  3. It stays constant
  4. It doubles each period

Question 12

Which electron arrangement makes Group 0 elements unreactive?
  1. A stable full outer shell
  2. One outer electron to lose
  3. Seven outer electrons to gain
  4. A partly filled outer shell

Question 13

Which halogen can displace bromine from potassium bromide solution?
  1. Chlorine
  2. Iodine
  3. Astatine
  4. Neon

Question 14

A sample has \(60\%\) isotope X-\(20\) and \(40\%\) isotope X-\(22\). What is the relative atomic mass?
  1. \(20.8\)
  2. \(21.0\)
  3. \(20.0\)
  4. \(22.0\)

Question 15

Aluminium-\(27\) forms Al3+. How many electrons are in Al3+?
  1. \(10\)
  2. \(13\)
  3. \(14\)
  4. \(27\)

Question 16

What is relative atomic mass?
  1. Weighted mean mass of an element's isotopes
  2. The number of protons
  3. The mass of one atom in grams
  4. The number of shells

Question 17

Which particles are counted in an atom's mass number?
  1. Protons and neutrons
  2. Protons only
  3. Neutrons only
  4. Protons and electrons

Question 18

What happens when an atom loses an electron?
  1. It forms a positive ion
  2. It forms a negative ion
  3. It becomes a neutron
  4. It gains a proton

Question 19

What forms when an atom gains an electron?
  1. A negative ion
  2. A positive ion
  3. A different isotope
  4. The next element

Question 20

What does Group 1 in the periodic table show?
  1. Elements with one electron in the outer shell
  2. Elements with one proton in each nucleus
  3. Elements with one neutron in each nucleus
  4. Elements with a full outer electron shell

Question 21

What charge does a Group 7 atom have after gaining one electron?
  1. 1−
  2. 1+
  3. 2−
  4. 0

Question 22

Which atomic model placed electrons within a sphere of positive charge?
  1. The plum-pudding model
  2. Dalton's solid-sphere model
  3. Rutherford's nuclear model
  4. Bohr's shell model

Question 23

Which property orders elements in the modern periodic table?
  1. Atomic number
  2. Relative atomic mass
  3. Number of electron shells
  4. State at room temperature

Question 24

Where are transition metals in the periodic table?
  1. In the centre
  2. At the far left
  3. At the far right
  4. Across the top row

Question 25

What is a compound?
  1. Elements chemically bonded together
  2. Elements simply mixed together
  3. Atoms of one kind only
  4. Atoms with different neutron numbers

Question 26

Compared with Group 1 metals, transition metals are generally what?
  1. Less reactive
  2. More reactive
  3. Softer
  4. Lower melting

Question 27

How did Mendeleev order the elements in his periodic table?
  1. By atomic weight
  2. By atomic number
  3. By alphabetical name
  4. By increasing density

Question 28

Where are the non-metals found in the periodic table?
  1. On the right-hand side
  2. On the left-hand side
  3. In the central block
  4. In the bottom two rows

Question 29

Which statement is true of a mixture?
  1. Its parts are not chemically bonded
  2. Its parts are chemically bonded
  3. It has a fixed chemical formula
  4. It melts at a single temperature

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Review Atomic Structure questions for Chemistry, with correct answers shown and coverage across protons, neutrons and electrons; atomic number and mass number; isotopes and relative atomic mass.

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