CHEM 121 EXAM SCRIPT 2025/2026 QUESTIONS WITH ANSWERS GRADED A+

CHEM 121 EXAM SCRIPT 2025/2026 QUESTIONS WITH
ANSWERS GRADED A+
✔✔How many protons are found in the nucleus of boron-11 (b) atom?
1) 11
2) 6
3) 5
4) 4 - ✔✔3) 5

✔✔How many silicon atoms (Si) are contained in a 12.5g sample of silicon?
1) 2.68' 10^23
2) 5.83' 10^-22
3) 1.35' 10^ 24
4) 1.71' 10^21 - ✔✔1) 2.68' 10^23

✔✔Determine the molecular weight of hydrogen peroxide, H2O2 in u.
1) 17.01
2) 18.02
3) 34.02
4) 33.01 - ✔✔3) 34.02

✔✔How many moles of Oxygen atoms are in one mole of CO2?
1) 1
2) 2
3) 6.02' 10^23
4) 12.04' 10^23 - ✔✔2) 2

✔✔Which of the following particles is the smallest?
1) proton
2) electron
3) neutron
4) they are all the same size - ✔✔2) electron

✔✔What mass of arsenic (As) in grams contains the same number of atoms as 39.95g
of argon (Ar)?
1) 33.0
2) 74.92
3) 4.16
4) 149.84 - ✔✔2) 74.92

✔✔How many electrons are in a neutral atom of carbon-13, 13C?
1) 6
2) 18
3) 12

, 4) no way to tell - ✔✔1) 6

✔✔Which of the following elements is classified as as transition element?
1) element 76
2) element 60
3) element 56
4) element 17 - ✔✔1) element 76

✔✔Which of the following distinguishing electrons represents an element with
properties similar to an element with 3p^3 distinguishing electron?
1) 4p^3
2) 3p^2
3) 3d^3
4) 2p^2 - ✔✔1) 4p^3

✔✔The total number of f orbital in an f subshell is
1) 2
2) 5
3) 7
4) 10 - ✔✔3) 7

✔✔Which of the following elements has an electronic configuration of 1s^2 2s^2 2p^6
3s^2 3p^1
1) F
2) Al
3) Mg
4) Ga - ✔✔2) Al

✔✔Which of the following elements is most likely to be a metalloid?
1) Ge
2) Mo
3) S
4) Cs - ✔✔1) Ge

✔✔Which of the following elements is found in the same period of the periodic table as
Sn?
1) Si
2) As
3) Te
4) more than one response is correct - ✔✔3) Te

✔✔How many electrons are in the outer shell of element 15?
1) 5
2) 3