Question

1. fill in the following chart. (assume all atoms are electrically neutral.)

element symbol atomic number mass number # of protons # of neutrons # of electrons
o 16
13 14
31 15
20 19
br 80
30 65
82 125
120 53
44 58
hg 198
55 70
80

Explanation:

Step1: Recall atomic - related concepts

For an electrically neutral atom, the number of protons = atomic number = number of electrons, and mass number = number of protons+number of neutrons.

Step2: For oxygen (O)

Atomic number of O is 8. Given mass number = 16, number of protons = 8, number of neutrons = mass number - number of protons = 16 - 8=8, number of electrons = 8.

Step3: For atomic number 13

The element is Al (aluminum). Mass number = number of protons+number of neutrons = 13 + 14=27, number of electrons = 13.

Step4: For number of protons = 15

The element is P (phosphorus). Atomic number = 15, mass number = 31, number of neutrons = 31 - 15 = 16, number of electrons = 15.

Step5: For number of electrons = 19

Atomic number = 19 (K, potassium). Mass number = number of protons+number of neutrons = 19+20 = 39.

Step6: For element Br

Atomic number of Br is 35. Given mass number = 80, number of protons = 35, number of neutrons = 80 - 35=45, number of electrons = 35.

Step7: For atomic number 30

The element is Zn (zinc). Mass number = 65, number of protons = 30, number of neutrons = 65 - 30 = 35, number of electrons = 30.

Step8: For number of protons = 82

The element is Pb (lead). Atomic number = 82, mass number = number of protons+number of neutrons = 82+125 = 207, number of electrons = 82.

Step9: For number of electrons = 53

Atomic number = 53 (I, iodine). Mass number = number of protons+number of neutrons = 53+(126 - 53)=126.

Step10: For atomic number 44

The element is Ru (ruthenium). Mass number = number of protons+number of neutrons = 44+58 = 102, number of electrons = 44.

Step11: For element Hg

Atomic number of Hg is 80. Given number of protons = 80, mass number = 198, number of neutrons = 198 - 80=118, number of electrons = 80.

Step12: For number of protons = 55

The element is Cs (cesium). Atomic number = 55, mass number = number of protons+number of neutrons = 55+70 = 125, number of electrons = 55.

Element symbol	Atomic number	Mass number	# of protons	# of neutrons	# of electrons
Al	13	27	13	14	13
P	15	31	15	16	15
K	19	39	19	20	19
Br	35	80	35	45	35
Zn	30	65	30	35	30
Pb	82	207	82	125	82
I	53	126	53	73	53
Ru	44	102	44	58	44
Hg	80	198	80	118	80
Cs	55	125	55	70	55

Answer:

See the filled - in table above.