Question

practice: atomic calculations
part 1 atomic structure
1 draw five protons in the atom to the right. label them with their charge.
2 draw six neutrons in the atom to the right. label them with their charge.
3 draw five electrons in the atom to the right. place two on the first energy level and three on the second. label them with their charge.

1. what element did you just draw?
2. how do you know?

part 2 periodic table
6 label each part of the periodic - table notation shown to the right
7 how do you know the number of protons in an atom?

1. how do you know the number of neutrons?

9 how do you know the number of electrons?
part 3 atomic calculations: complete the chart below.
10.

element	atomic #	mass #	# of p⁺	# of n⁰	# of e⁻
p	15	31
h	1	1	1
mn	25	55		30
k	19	39
ag	47	108		61
cl	17	35	17
si	14	28		14
			74	110
			10	10

Explanation:

Step1: Recall atomic structure basics

The atomic number is equal to the number of protons. In a neutral atom, the number of electrons equals the number of protons, and the number of neutrons is the mass - number minus the atomic number.

Step2: Fill in the chart for Li

Atomic number of Li is 3, so number of protons ($p^{+}$) = 3. Mass number is 7, number of neutrons ($n^{0}$)=7 - 3=4. In a neutral atom, number of electrons ($e^{-}$)=3.

Step3: Fill in the chart for P

Atomic number of P is 15, so number of protons ($p^{+}$) = 15. Mass number is 31, number of neutrons ($n^{0}$)=31 - 15 = 16. In a neutral atom, number of electrons ($e^{-}$)=15.

Step4: Fill in the chart for H

Atomic number of H is 1, so number of protons ($p^{+}$) = 1. Mass number is 1, number of neutrons ($n^{0}$)=1 - 1=0. In a neutral atom, number of electrons ($e^{-}$)=1.

Step5: Fill in the chart for Mn

Atomic number of Mn is 25, so number of protons ($p^{+}$) = 25. Given number of neutrons ($n^{0}$)=30. Mass number = 25+30 = 55. In a neutral atom, number of electrons ($e^{-}$)=25.

Step6: Fill in the chart for K

Atomic number of K is 19, so number of protons ($p^{+}$) = 19. Mass number is 39, number of neutrons ($n^{0}$)=39 - 19 = 20. In a neutral atom, number of electrons ($e^{-}$)=19.

Step7: Fill in the chart for Ag

Atomic number of Ag is 47, so number of protons ($p^{+}$) = 47. Given number of neutrons ($n^{0}$)=61. Mass number = 47+61 = 108. In a neutral atom, number of electrons ($e^{-}$)=47.

Step8: Fill in the chart for Cl

Atomic number of Cl is 17, so number of protons ($p^{+}$) = 17. Mass number is 35, number of neutrons ($n^{0}$)=35 - 17 = 18. In a neutral atom, number of electrons ($e^{-}$)=17.

Step9: Fill in the chart for Si

Atomic number of Si is 14, so number of protons ($p^{+}$) = 14. Given number of neutrons ($n^{0}$)=14. Mass number = 14 + 14=28. In a neutral atom, number of electrons ($e^{-}$)=14.

Step10: For the last row

Number of neutrons ($n^{0}$)=74, number of protons ($p^{+}$) is unknown. Mass number = 74+110 = 184. In a neutral atom, number of electrons ($e^{-}$) is equal to number of protons. Since number of neutrons is 74 and mass number is 184, number of protons ($p^{+}$)=184 - 74=110, and number of electrons ($e^{-}$)=110.
The last element with atomic number 10 and mass number 20 (assuming from number of neutrons 10 and protons 10) is Ne.

Answer:

Element	Atomic #	Mass #	# of $p^{+}$	# of $n^{0}$	# of $e^{-}$
P	15	31	15	16	15
H	1	1	1	0	1
Mn	25	55	25	30	25
K	19	39	19	20	19
Ag	47	108	47	61	47
Cl	17	35	17	18	17
Si	14	28	14	14	14
-	-	184	110	74	110
Ne	10	20	10	10	10

For the other questions:

1. Draw five positively - charged ($+ 1$) protons in the nucleus of the atom.
2. Draw six neutrons with no charge (0) in the nucleus of the atom.
3. Draw five negatively - charged ($-1$) electrons, two in the first energy level and three in the second energy level.
4. The element drawn is Boron (B).
5. We know it is Boron because the number of protons is 5, and the atomic number of an element is determined by the number of protons. Boron has an atomic number of 5.
6. For the periodic table notation of oxygen: The top number 8 is the atomic number (number of protons), the symbol O is for oxygen, and 16.00 is the average atomic mass.
7. The number of protons in an atom is equal to the atomic number of the element, which is given on the periodic table.
8. The number of neutrons can be found by subtracting the atomic number from the mass number (Mass number - Atomic number = Number of neutrons).
9. In a neutral atom, the number of electrons is equal to the number of protons. If the atom is an ion, the number of electrons is adjusted according to the charge of the ion.