Question

atomic structure practice
complete the following table.
remember that if a charge or a difference in electrons and protons is not given to you, assume the atom is neutral*

symbol notation	atomic number	number of protons	mass number	number of neutrons	number of electrons
	19		39		19
	38		50		36
$_{20}^{40}ca^{ + 2}$	20		40
	35		45		36
	43		55		43
$_{12}^{25}mg^{+2}$		12	25
$_{9}^{19}f^{1}$	9		19
	53		73		54
	47		110
$_{16}^{32}s^{-2}$	16		32		46

Explanation:

Step1: Recall atomic - structure relationships

For a neutral atom, the number of protons = number of electrons. The mass number = number of protons+number of neutrons. For an ion, adjust the number of electrons according to the charge.

Step2: Fill the first row

Atomic number = 51, so number of protons = 51. Mass number = 122, number of neutrons = 122 - 51=71. Since number of electrons = 51, assume neutral, symbol notation: $^{122}_{51}Sb$ (antimony).

Step3: Fill the second row

Atomic number = 19, so number of protons = 19. Mass number = 39, number of neutrons = 39 - 19 = 20. Since number of electrons = 19, assume neutral, symbol notation: $^{39}_{19}K$ (potassium).

Step4: Fill the third row

Number of protons = 38, atomic number = 38. Mass number = number of protons+number of neutrons = 38 + 50=88. Since number of electrons = 36, it is a 2+ ion, symbol notation: $^{88}_{38}Sr^{2 + }$ (strontium).

Step5: Fill the fourth row

Atomic number = 20, number of protons = 20. Mass number = 40, number of neutrons = 40 - 20 = 20. Given $Ca^{2+}$, number of electrons = 20 - 2 = 18.

Step6: Fill the fifth row

Atomic number = 35, number of protons = 35. Mass number = number of protons+number of neutrons = 35+45 = 80. Since number of electrons = 36, it is a 1 - ion, symbol notation: $^{80}_{35}Br^{-}$ (bromine).

Step7: Fill the sixth row

Atomic number = 43, number of protons = 43. Mass number = 43+55 = 98. Since number of electrons = 43, assume neutral, symbol notation: $^{98}_{43}Tc$ (technetium).

Step8: Fill the seventh row

Atomic number = 12, number of protons = 12. Mass number = 25, number of neutrons = 25 - 12 = 13. Given $Mg^{2+}$, number of electrons = 12 - 2 = 10.

Step9: Fill the eighth row

Atomic number = 9, number of protons = 9. Mass number = 19, number of neutrons = 19 - 9 = 10. Given $F^{-}$, number of electrons = 9+1 = 10.

Step10: Fill the ninth row

Atomic number = 53, number of protons = 53. Mass number = 53+73 = 126. Since number of electrons = 54, it is a 1 - ion, symbol notation: $^{126}_{53}I^{-}$ (iodine).

Step11: Fill the tenth row

Atomic number = 47, number of protons = 47. Mass number = 110, number of neutrons = 110 - 47 = 63. Since number of electrons = 45, it is a 2+ ion, symbol notation: $^{110}_{47}Ag^{2+}$ (silver).

Step12: Fill the eleventh row

Atomic number = 16, number of protons = 16. Mass number = 32, number of neutrons = 32 - 16 = 16. Given $S^{2 - }$, number of electrons = 16+2 = 18.

Symbol Notation	Atomic Number	Number of Protons	Mass Number	Number of Neutrons	Number of Electrons
$^{39}_{19}K$	19	19	39	20	19
$^{88}_{38}Sr^{2+}$	38	38	88	50	36
$^{40}_{20}Ca^{2+}$	20	20	40	20	18
$^{80}_{35}Br^{-}$	35	35	80	45	36
$^{98}_{43}Tc$	43	43	98	55	43
$^{25}_{12}Mg^{2+}$	12	12	25	13	10
$^{19}_{9}F^{-}$	9	9	19	10	10
$^{126}_{53}I^{-}$	53	53	126	73	54
$^{110}_{47}Ag^{2+}$	47	47	110	63	45
$^{32}_{16}S^{2 - }$	16	16	32	16	18

Answer:

Symbol Notation	Atomic Number	Number of Protons	Mass Number	Number of Neutrons	Number of Electrons
$^{39}_{19}K$	19	19	39	20	19
$^{88}_{38}Sr^{2+}$	38	38	88	50	36
$^{40}_{20}Ca^{2+}$	20	20	40	20	18
$^{80}_{35}Br^{-}$	35	35	80	45	36
$^{98}_{43}Tc$	43	43	98	55	43
$^{25}_{12}Mg^{2+}$	12	12	25	13	10
$^{19}_{9}F^{-}$	9	9	19	10	10
$^{126}_{53}I^{-}$	53	53	126	73	54
$^{110}_{47}Ag^{2+}$	47	47	110	63	45
$^{32}_{16}S^{2 - }$	16	16	32	16	18