Question

name:
date:
worksheet #2 - calculating protons, electrons, and neutrons
element
symbol
atomic
number
atomic mass
protons
electrons
neutrons
h
1
1

2

2

li

7

be
4
9

5

5

6
c

12

7
14

o

16

8
f
9

ne

20

11
23

12
12
al

14

15
31

32

cl
17

ar

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Explanation:

Step1: Proton and Electron Relationship

For a neutral atom, the number of protons is equal to the atomic number, and the number of electrons is equal to the number of protons.

Step2: Neutron Calculation

The number of neutrons is calculated as \( \text{Neutrons}=\text{Atomic Mass}-\text{Atomic Number}\)

For \(H\):

• Protons \( = 1\) (atomic number)
• Electrons \(=1\) (since it's neutral)
• Neutrons \(=1 - 1=0\)

For the element with atomic number \(2\):

• Symbol is \(He\)
• Protons \(=2\)
• Electrons \(=2\)
• Atomic Mass \(=2 + 2=4\)

For \(Li\):

• Atomic number \(=3\) (from periodic table, \(Li\) is the 3rd element)
• Protons \(=3\)
• Electrons \(=3\)
• Neutrons \(=7 - 3=4\)

For \(Be\):

• Protons \(=4\) (atomic number)
• Electrons \(=4\)

For the element with atomic number \(5\):

• Symbol is \(B\)
• Protons \(=5\)
• Electrons \(=5\)
• Atomic Mass \(=5 + 6=11\)

For \(C\):

• Atomic number \(=6\)
• Protons \(=6\)
• Electrons \(=6\)
• Neutrons \(=12 - 6=6\)

For the element with atomic number \(7\):

• Symbol is \(N\)
• Protons \(=7\)
• Electrons \(=7\)
• Neutrons \(=14 - 7=7\)

For \(O\):

• Atomic number \(=8\)
• Protons \(=8\)
• Electrons \(=8\)

For \(F\):

• Atomic Mass \(=9 + 10=19\) (since neutrons \(=10\) as \(19-9 = 10\))
• Protons \(=9\)
• Electrons \(=9\)

For \(Ne\):

• Atomic number \(=10\)
• Protons \(=10\)
• Electrons \(=10\)
• Neutrons \(=20 - 10=10\)

For the element with atomic number \(11\):

• Symbol is \(Na\)
• Protons \(=11\)
• Electrons \(=11\)
• Neutrons \(=23 - 11=12\)

For the element with protons \(12\):

• Atomic number \(=12\) (symbol \(Mg\))
• Electrons \(=12\)
• Atomic Mass \(=12 + 12=24\)

For \(Al\):

• Atomic number \(=13\)
• Protons \(=13\)
• Electrons \(=13\)
• Atomic Mass \(=27\) (common isotope), neutrons \(=27-13 = 14\)

For the element with atomic number \(14\):

• Symbol is \(Si\)
• Protons \(=14\)
• Electrons \(=14\)
• Atomic Mass (common isotope) \(=28\), neutrons \(=28 - 14=14\)

For the element with atomic number \(15\):

• Symbol is \(P\)
• Protons \(=15\)
• Electrons \(=15\)
• Neutrons \(=31 - 15=16\)

For the element with atomic mass \(32\):

• If we assume it's \(S\) (atomic number \(16\))
• Protons \(=16\)
• Electrons \(=16\)
• Neutrons \(=32 - 16=16\)

For \(Cl\):

• Atomic Mass (common isotope) \(=35\)
• Protons \(=17\)
• Electrons \(=17\)
• Neutrons \(=35 - 17=18\)

For \(Ar\):

• Atomic number \(=18\)
• Protons \(=18\)
• Electrons \(=18\)
• Atomic Mass (common isotope) \(=40\), neutrons \(=40 - 18=22\)

Answer:

Element Symbol	Atomic Number	Atomic Mass	Protons	Electrons	Neutrons
\(He\)	\(2\)	\(4\)	\(2\)	\(2\)	\(2\)
\(Li\)	\(3\)	\(7\)	\(3\)	\(3\)	\(4\)
\(Be\)	\(4\)	\(9\)	\(4\)	\(4\)	\(5\)
\(B\)	\(5\)	\(11\)	\(5\)	\(5\)	\(6\)
\(C\)	\(6\)	\(12\)	\(6\)	\(6\)	\(6\)
\(N\)	\(7\)	\(14\)	\(7\)	\(7\)	\(7\)
\(O\)	\(8\)	\(16\)	\(8\)	\(8\)	\(8\)
\(F\)	\(9\)	\(19\)	\(9\)	\(9\)	\(10\)
\(Ne\)	\(10\)	\(20\)	\(10\)	\(10\)	\(10\)
\(Na\)	\(11\)	\(23\)	\(11\)	\(11\)	\(12\)
\(Mg\)	\(12\)	\(24\)	\(12\)	\(12\)	\(12\)
\(Al\)	\(13\)	\(27\)	\(13\)	\(13\)	\(14\)
\(Si\)	\(14\)	\(28\)	\(14\)	\(14\)	\(14\)
\(P\)	\(15\)	\(31\)	\(15\)	\(15\)	\(16\)
\(S\)	\(16\)	\(32\)	\(16\)	\(16\)	\(16\)
\(Cl\)	\(17\)	\(35\)	\(17\)	\(17\)	\(18\)
\(Ar\)	\(18\)	\(40\)	\(18\)	\(18\)	\(22\)