Emt 1 a chem

1. Which statement best describes the structure of an atom?

Atoms have a small, dense nucleus containing protons and neutrons, with electrons in shells around it Atoms are solid spheres with electrons embedded throughout Atoms have a large nucleus containing electrons, with protons orbiting around it Atoms are mostly empty space with electrons and protons randomly distributed

2. What are the relative charges of protons, neutrons, and electrons respectively?

\( +1, 0, -1 \) \( +1, +1, -1 \) \( -1, 0, +1 \) \( 0, +1, -1 \)

3. The atomic number of an element represents:

The number of protons in the nucleus The number of neutrons in the nucleus The total number of protons and neutrons The number of electrons in the outer shell

4. Isotopes of the same element have:

The same number of protons but different numbers of neutrons The same number of neutrons but different numbers of protons The same mass number but different atomic numbers The same number of electrons but different numbers of protons

5. Which of the following is NOT true about isotopes of the same element?

They have the same chemical properties They have the same physical properties They have the same number of protons They have different mass numbers

6. In the notation \(^{35}_{17}\text{Cl}\), the number 35 represents:

The atomic number The number of protons The mass number The number of electrons

7. Which of the following statements about electron shells is correct?

The principal quantum number (\(n\)) determines the energy of an electron shell All electron shells contain the same number of electrons Electron shells are all at the same distance from the nucleus The first shell can hold up to 10 electrons

8. How many electrons can occupy a p orbital?

2 6 8 10

9. Which of the following electronic configurations represents a free radical?

A species with all electrons paired A species with one or more unpaired electrons A species with a full outer shell A species with no electrons

10. The first ionisation energy of an element is defined as:

The energy required to remove one electron from each atom in one mole of gaseous atoms The energy required to add one electron to each atom in one mole of gaseous atoms The energy released when one electron is added to each atom in one mole of gaseous atoms The energy required to remove the nucleus from one mole of atoms

11. Which factor does NOT affect the ionisation energy of an element?

Nuclear charge Atomic radius Shielding by inner electrons The element's state at room temperature

12. Across a period in the Periodic Table, atomic radius generally:

Increases Decreases Remains constant First increases then decreases

13. Down a group in the Periodic Table, ionisation energy generally:

Increases Decreases Remains constant First decreases then increases

14. Which of the following elements would have the highest first ionisation energy?

Sodium (Na) Magnesium (Mg) Aluminium (Al) Silicon (Si)

15. The shape of an s orbital is:

Spherical Dumbbell Cloverleaf Complex with multiple lobes

16. How many orbitals are in a p sub-shell?

1 3 5 7

17. Which of the following electronic configurations represents the ground state of nitrogen (atomic number 7)?

\(1s^2 2s^2 2p^3\) \(1s^2 2s^1 2p^4\) \(1s^2 2s^2 2p^2 3s^1\) \(1s^2 2s^2 2p^5\)

18. The second ionisation energy of an element is always greater than the first because:

The electron is being removed from a positively charged ion The electron is being removed from a higher energy level The electron is closer to the nucleus There is less shielding

19. Which of the following elements would show the largest jump between its first and second ionisation energies?

Lithium (Li) Beryllium (Be) Boron (B) Carbon (C)

20. In the ground state electronic configuration of an atom, electrons fill orbitals in order of:

Increasing energy Decreasing energy Random order Alphabetical order of orbital names

21. Which of the following statements about atomic orbitals is correct?

An orbital can hold a maximum of two electrons with opposite spins All orbitals in the same sub-shell have different energies The 3d orbitals are filled before the 4s orbital The 2p orbitals are spherical in shape

22. The notation \(1s^2 2s^2 2p^6 3s^2 3p^6 4s^1\) represents the electronic configuration of:

Potassium (K) Calcium (Ca) Sodium (Na) Argon (Ar)

23. Which of the following is NOT a factor that affects atomic radius?

Nuclear charge Number of electron shells Shielding effect of inner electrons The element's melting point

24. The Pauli Exclusion Principle states that:

No two electrons in an atom can have the same set of four quantum numbers Electrons fill orbitals of lowest energy first Electrons occupy degenerate orbitals singly before pairing up An orbital can hold a maximum of two electrons

25. Hund's Rule states that:

Electrons fill orbitals of lowest energy first No two electrons in an atom can have the same set of four quantum numbers Electrons occupy degenerate orbitals singly before pairing up An orbital can hold a maximum of two electrons

26. Which of the following elements has the smallest atomic radius?

Lithium (Li) Sodium (Na) Potassium (K) Rubidium (Rb)

27. Which of the following elements has the highest first ionisation energy?

Helium (He) Neon (Ne) Argon (Ar) Krypton (Kr)

28. The Aufbau Principle states that:

Electrons fill orbitals of lowest energy first No two electrons in an atom can have the same set of four quantum numbers Electrons occupy degenerate orbitals singly before pairing up An orbital can hold a maximum of two electrons

29. Which of the following statements about isotopes is correct?

Isotopes have the same number of protons but different numbers of neutrons Isotopes have the same number of neutrons but different numbers of protons Isotopes have different chemical properties Isotopes have the same physical properties

30. The electronic configuration of chromium (Cr, atomic number 24) is an exception to the Aufbau principle. Its ground state configuration is:

\(1s^2 2s^2 2p^6 3s^2 3p^6 4s^2 3d^4\) \(1s^2 2s^2 2p^6 3s^2 3p^6 4s^1 3d^5\) \(1s^2 2s^2 2p^6 3s^2 3p^6 4s^2 3d^5\) \(1s^2 2s^2 2p^6 3s^2 3p^6 4s^1 3d^4\)

Chemistry Quiz: Atomic Structure

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