Question

chemistry atomic structure practice 1
x = element symbol
a = mass number # of protons (p) + # neutrons (n)
z = atomic number # of protons
n = # of neutrons
a - z = n
a typical isotopic symbol takes this form: $_{z}^{a}x$
ex. the isotopic symbol for fluorine would be $_{9}^{19}f$
fill in the missing items in the table below.
name symbol z a #p #e #n isotopic symbol
sodium na 11 23 11 11 12 $_{11}^{23}na$
chlorine cl 17 35 17 17 18 $_{17}^{35}cl$
potassium k 19 39 19
fill in the missing items in the table below.
name symbol z a #p #e #n isotopic symbol
p 31
iron 56
53 127
fill in the missing items in the table below.
name symbol z a #p #e #n isotopic symbol
silver 108
36 84
w 184

Explanation:

Step1: Recall atomic - structure relationships

Atomic number \(Z =\) number of protons \(\#p\), for a neutral atom, number of electrons \(\#e=\) number of protons \(\#p\), and number of neutrons \(\#n=A - Z\), and the isotopic symbol is \(_{Z}^{A}X\).

Step2: Complete Sodium (Na) row

Given \(Z = 11\), \(A = 23\). \(\#p=Z = 11\), \(\#e=\#p = 11\), \(\#n=A - Z=23 - 11 = 12\), isotopic symbol is \(_{11}^{23}Na\).

Step3: Complete Chlorine (Cl) row

Given \(Z = 17\), \(A = 35\). \(\#p = 17\), \(\#e=\#p = 17\), \(\#n=A - Z=35 - 17 = 18\), isotopic symbol is \(_{17}^{35}Cl\).

Step4: Complete Potassium (K) row

Given \(Z = 19\), \(A = 39\). \(\#p = 19\), \(\#e=\#p = 19\), \(\#n=A - Z=39 - 19 = 20\), isotopic symbol is \(_{19}^{39}K\).

Step5: Complete Phosphorus (P) row

\(Z\) for \(P\) is \(15\), \(A = 31\), \(\#p=Z = 15\), \(\#e=\#p = 15\), \(\#n=A - Z=31 - 15 = 16\), isotopic symbol is \(_{15}^{31}P\).

Step6: Complete Iron (Fe) row

\(Z\) for \(Fe\) is \(26\), \(A = 56\), \(\#p=Z = 26\), \(\#e=\#p = 26\), \(\#n=A - Z=56 - 26 = 30\), isotopic symbol is \(_{26}^{56}Fe\).

Step7: Complete Iodine - like row

Given \(\#p = 53\), so \(Z = 53\), \(A = 127\), \(\#e=\#p = 53\), \(\#n=A - Z=127 - 53 = 74\), isotopic symbol is \(_{53}^{127}I\).

Step8: Complete Silver (Ag) row

\(Z\) for \(Ag\) is \(47\), \(A = 108\), \(\#p=Z = 47\), \(\#e=\#p = 47\), \(\#n=A - Z=108 - 47 = 61\), isotopic symbol is \(_{47}^{108}Ag\).

Step9: Complete Krypton - like row

Given \(Z = 36\), \(A = 84\), \(\#p=Z = 36\), \(\#e=\#p = 36\), \(\#n=A - Z=84 - 36 = 48\), isotopic symbol is \(_{36}^{84}Kr\).

Step10: Complete Tungsten (W) row

\(Z\) for \(W\) is \(74\), \(A = 184\), \(\#p=Z = 74\), \(\#e=\#p = 74\), \(\#n=A - Z=184 - 74 = 110\), isotopic symbol is \(_{74}^{184}W\).

Answer:

Name	Symbol	Z	A	#p	#e	#n	Isotopic Symbol
Chlorine	Cl	17	35	17	17	18	\(_{17}^{35}Cl\)
Potassium	K	19	39	19	19	20	\(_{19}^{39}K\)
Phosphorus	P	15	31	15	15	16	\(_{15}^{31}P\)
Iron	Fe	26	56	26	26	30	\(_{26}^{56}Fe\)
Iodine	I	53	127	53	53	74	\(_{53}^{127}I\)
Silver	Ag	47	108	47	47	61	\(_{47}^{108}Ag\)
Krypton	Kr	36	84	36	36	48	\(_{36}^{84}Kr\)
Tungsten	W	74	184	74	74	110	\(_{74}^{184}W\)