Horizon International School
C C
hemistry
ompetition
Answer key
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Answer
Question
Answer
Name:_________________Grade 9
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Choose the best answer from the options that follow each question.
____
1. Which of the following quantum numbers describes a p-orbital in the third energy level?
a. n = 3, l = 0, m = 0
b. n = 3, l = 1, m = 0
c. n = 3, l = 1, m = 0
d. n = 4, l = 1, m = 0
____
2. What is the frequency of light whose wavelength is 633 nm?
a. 4.74 10-4 Hz
b. 4.74 10-2 Hz
c. 4.74 1014 Hz
d. 4.74 1016 Hz
____
3. Which are the sublevels in an energy level of n
a. s, p, and f
b. s, d, and f
c. s, p, and d
d. p, d, and f
____
4. What is the correct electron configuration for a ground-state atom with 7 electrons?
a. 1s22s22p3
b. 1s22s22p23s1
c. 1s22s32p2
d. 1s22s5
____
5. What is the correct noble-gas notation for the electron configuration of an atom of chlorine (17)?
a. [Ar]3s23p5
b. [Ne]3s23p4
c. [Ar]3s23p4
d. [Ne]3s23p5
____
6. What is the atomic number of the element with the noble-gas notation [Kr]5s1?
a. 35
b. 36
c. 37
d. 38
____
7. In which orbital(s) are all the inner-shell electrons located in an atom of magnesium that is in the ground
state?
a. 1s
b. 1s, 2s
c. 1s, 2s, 2p
d. 1s, 2s, 2p, 3s
____
8. The electron configuration below represents a ground-state atom of which element?
1s22s22p63s23p4
a. sulfur
b. oxygen
c. silicon
d. selenium
3?
2
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9. What is the total number of electrons needed to fill the fourth main energy level?
a. 4
b. 8
c. 16
d. 32
____ 10. An orbital that would never exist in the quantum description of an atom is
a. 3d.
b. 8s.
c. 6d.
d. 3f.
____ 11. When electrons change energy states, the amount of energy given off or absorbed is equal to
a. hc.
b. hv.
c. n.
d. cv.
____ 12. An electron occupies the lowest energy orbital that can receive it.
a. Hunds’s rule
b. Pauli exclusion principle
c. Bohr model of the atom
d. Aufbau principle
____ 13. What is the correct notation for a calcium ion whose outershell is a full octet?
a. Ca1+
b. Ca2+
c. Ca1d. Ca2____ 14. What is the correct name for the NO ion?
a. nitrate
b. nitrite
c. nitride
d. nitrogen oxide
____ 15. What is the correct formula for copper(I) cyanide?
a. CuCy
b. CuCy2
c. CuCN
d. Cu2CN
____ 16. What is the correct name for the compound P2Cl4.
a. phosphorus chloride
b. phosphorus tetrachloride
c. diphosphorus chloride
d. diphosphorus tetrachloride
____ 17. What is the correct formula for the compound made of magnesium and nitrogen?
a. Mg2N3
b. Mg3N2
c. MgN2
d. MgN
3
____ 18. What is the correct name for the compound Ni2O3 using the Stock system?
a. nickel(II) oxide
b. dinickel trioxide
c. nickel trioxide
d. nickel(III) oxide
____ 19. What is the mass of 2.2 mol of Water (18 g/mol)?
a. 4.80 g
b. 39.6 g
c. 139 g
d. 669 g
____ 20. What is the correct formula for the compound platinum(VI) fluoride?
a. PtF3
b. PtF6
c. Pt6F2
d. Pt6F
____ 21. What is the molar mass of pure tin?
a. 1.00 g/mol
b. 47.88 g/mol
c. 118.71 g/mol
d. 237.42 g/mol
____ 22. How many moles of compound are there in 15.0 g of potassium dichromate, K2Cr2O7? (The molar mass of
K2Cr2O7 is 294.2 g.)
a. 0.0510 mol
b. 11.0 mol
c. 15.0 mol
d. 294 mol
____ 23. What is the mass of 4.80 mol of barium hydride, BaH2?
a. 4.80 g
b. 29.0 g
c. 139 g
d. 669 g
____ 24. The platinum(II) ion and the platinum(IV) ion
a. are anions.
b. are polyatomic ions.
c. have charges of 2+and 4+, respectively.
d have charges of 1+ and 3+, respectively.
____ 25. What is the name of the compound made of zinc ions, Zn2+, and fluoride ions, F-?
a. zinc difluoride
b. zinc fluorate
c. zinc fluoride
d. zinc(II) fluorite
____ 26. What is the chemical formula for the compound made of tin(IV) ions and chloride, Cl-, ions?
a. SnCl4
b. Sn2Cl2
c. SnCl2
d. Sn4Cl
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____ 27. What is the correct formula for the compound made of Sodium and Oxygen?
a. Na2O
b. NaO2
c. NaO
d. Na2O2
____ 28. What is the atomic number of the element with the noble-gas notation [Ne]3s1?
a. 11
b. 9
c. 37
d. 10
____ 29. What is the name of the compound made of copper ions, Cu2+, and Hydroxide ions, OH-?
a. Copper (I) Hydroxide
b. copper Hydroxide
c. copper dihydroxide
d. copper (II) Hydroxide
____ 30. What is the correct formula for the compound Iron(III) fluoride?
a. FeF3
b. FeF6
c. F2Fe
d. Fe6F
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