Test Atomic Structure

1. What is the total number of electrons in the 2p sublevel of a chlorine atom in the ground state? (1) 6; (2) 2; (3) 3; (4) 5.
2. Which is the electron configuration of an atom in the excited state? (1) 1s1,2s ; (2) 1s2,2s2,2p1 ; (3) 1s2,2s2,2p; (4) 1s2,2s2,2p2,3s1
3. A Ca (+2) ion differs from a Ca atom in that the Ca (2+) ion has (1) more protons; (2) fewer protons; (3) more electrons; (4) fewer electrons.
4. At the end of 12 days, 1/4 of an original sample of a radioactive element remains. What is the half-life of the element? (1) 24 days; (2) 48 days; (3) 3 days; (4) 6 days.
5. The total number of orbitals in the 4f sublevel is (1) 1; (2) 5; (3) 3; (4) 7.
6. Which electron transition is accompanied by the emission of energy? (1) 1s to 2s; (2) 2s to 2p; (3) 3p to 3s; (4) 3p to 4p.
7. What is the total number of nucleons (protons and neutrons) in an atom of selenium (atomic no.=34, atomic mass= 79)? (1) 34; (2) 45; (3) 79; (4) 113.
8. What is the total number of principal energy levels that are completely filled in an atom of magnesium in the ground state? (1) 1; (2) 2; (3) 3; (4) 4.
9. What is the maximum number of electrons that can occupy the 4d sublevel? (1) 6; (2) 2; (3) 10; (4) 14.
10. Which sublevels are occupied in the outermost principal energy level of an argon atom in the ground state? (1) 3s and 3d; (2) 3s and 3p; (3) 2s and 3p; (4) 2p and 3d.
11. Which electron configuration represents an atom in the excited state? (1) 1s,2s2 ; (2) 1s2,3p1 ; (3) 1s2 ,2s2,2p5 ; (4) 1s2,2s2,2p6.
12. Which element has an atom in the ground state with the most loosely bound electron? (1) He; (2) As; (3) Xe; (4) Cs.
13. The half-life of C-14 is 5730 years. What fraction of a 1 gram sample of C-14 would remain after 17,190 years? (1) 1/2; (2) 1/4; (3) 1/8; (4) 1/16.
14. Isotopes of an element have a different (1) number of electrons; (2) number of protons; (3) atomic number; (4) mass number.
15. A neutral atom of an element has an electron configuration of 2-8-2. What is the total number of p electrons in this atom? (1) 6; (2) 2; (3) 10; (4) 12.
16. A neutral oxygen atom (O) differs from an oxide ion in that the atom has (1) more electrons; (2) fewer electrons; (3) more protons; (4) fewer protons.
17. Which is the electron configuration of a hydrogen atom with an atomic mass of 3 in1the ground state? (1) 1s; (2) 1s2; (3) 1s2,2s1; (4) 1s22,2s.
18. When an electron in an atom of hydrogen moves from the second to the first principal energy level then the result is the emission of (1) a beta particle; (2) an alpha particle; (3) quantized energy; (4) gamma rays.
19. How many occupied sublevels are in an atom of carbon in the ground state? (1) 5; (2) 6; (3) 3; (4) 4.
20. What is the total number of electrons in the 2nd principal energy level of a chlorine atom in the ground state? (1) 5; (2) 7; (3) 8; (4) 17.