Question

the structure of atoms
complete the table
sub - atomic particle symbol location in the atom mass of particle
proton
neutron
electron

1. what two sub - atomic particles are located in the nucleus of the atom?
2. what is the difference between the atomic number & the mass number of an element?
3. where is the majority of the mass located in an atom?

complete the table; the first two rows have been done for you. use your periodic table to complete the rest.
element symbol protons neutrons electrons
lithium li 3 7 - 3 = 4 3
carbon c 6 12 - 6 = 6 6
sodium
aluminum
pb
ti
zn
80
17
tungsten

Explanation:

Step1: Recall sub - atomic particle info

Proton: Symbol $p^+$, Location in the nucleus, Mass of particle approximately 1 amu.
Neutron: Symbol $n^0$, Location in the nucleus, Mass of particle approximately 1 amu.
Electron: Symbol $e^-$, Location outside the nucleus, Mass of particle approximately $\frac{1}{1836}$ amu.

Step2: Answer question 1

Protons and neutrons are located in the nucleus of the atom.

Step3: Answer question 2

The atomic number is the number of protons in an atom. The mass number is the sum of the number of protons and neutrons in an atom. So the difference is that the mass number includes neutrons while the atomic number does not.

Step4: Answer question 3

The majority of the mass is located in the nucleus because protons and neutrons, which have significant mass compared to electrons, are in the nucleus.

Step5: Complete second table

• Sodium: Symbol $Na$, Protons 11, Mass number (average) 23, Neutrons $23 - 11=12$, Electrons 11.
• Aluminum: Symbol $Al$, Protons 13, Mass number (average) 27, Neutrons $27 - 13 = 14$, Electrons 13.
• For $Pb$ (Lead): Protons 82, Mass number (average) 207, Neutrons $207 - 82=125$, Electrons 82.
• For $Ti$ (Titanium): Protons 22, Mass number (average) 48, Neutrons $48 - 22 = 26$, Electrons 22.
• For $Zn$ (Zinc): Protons 30, Mass number (average) 65, Neutrons $65 - 30=35$, Electrons 30.
• For the element with 80 protons, it is Mercury ($Hg$), Mass number (average) 200.6, Neutrons $200.6 - 80\approx121$, Electrons 80.
• For the element with 17 electrons (equal to protons in neutral atom), it is Chlorine ($Cl$), Protons 17, Mass number (average) 35.5, Neutrons $35.5 - 17\approx19$, Electrons 17.
• Tungsten ($W$): Symbol $W$, Protons 74, Mass number (average) 183.84, Neutrons $183.84 - 74\approx110$, Electrons 74.

Answer:

Sub - atomic Particle	Symbol	Location in the atom	Mass of particle
Neutron	$n^0$	Nucleus	Approximately 1 amu
Electron	$e^-$	Outside the nucleus	Approximately $\frac{1}{1836}$ amu

1. Protons and neutrons.
2. Atomic number is number of protons, mass number is sum of protons and neutrons.
3. In the nucleus.

Element	Symbol	Protons	Neutrons	Electrons
Carbon	$C$	6	6	6
Sodium	$Na$	11	12	11
Aluminum	$Al$	13	14	13
Lead	$Pb$	82	125	82
Titanium	$Ti$	22	26	22
Zinc	$Zn$	30	35	30
Mercury	$Hg$	80	121	80
Chlorine	$Cl$	17	19	17
Tungsten	$W$	74	110	74