Question

fill in the missing items in the table below. complete the table. use a periodic table where needed. there is enough information given for each element to determine all missing numbers. symbol atomic number mass number number of protons number of electrons number of neutrons ²³na k 40 19 38 38 52 f 10 20 41 18 50 50 72 ¹³¹i ²⁶mg 109 47 46

Explanation:

Step1: Recall atomic number rules

For a neutral atom, atomic number = number of protons = number of electrons. Also, mass number = number of protons+ number of neutrons.

Step2: First row ($^{23}$Na)

From periodic table, atomic number of Na (sodium) is 11. So number of protons = 11, number of electrons = 11. Mass number is 23, so number of neutrons = 23 - 11=12.

Step3: Second row (K)

Atomic number of K (potassium) from periodic table is 19. So number of protons = 19, mass number is given as 40, number of neutrons = 40 - 19 = 21.

Step4: Third row

Since number of protons = 38, from periodic table the element is Sr (strontium). Atomic number = 38, mass number = 38 + 52=90.

Step5: Fourth row (F)

Atomic number of F (fluorine) from periodic table is 9. So number of protons = 9, number of electrons = 9. Given number of neutrons = 10, mass number = 9+10 = 19.

Step6: Fifth row

Atomic number is 20, so the element is Ca (calcium). Number of protons = 20, mass number = 41, number of neutrons = 41 - 20 = 21. Given number of electrons = 18, it is a Ca$^{2 +}$ ion.

Step7: Sixth row

Since number of electrons = 50 (for neutral atom number of protons = number of electrons), atomic number = 50, the element is Sn (tin). Mass number = 50+72 = 122.

Step8: Seventh row ($^{131}$I)

Atomic number of I (iodine) from periodic table is 53. So number of protons = 53, number of electrons = 53, mass number is 131, number of neutrons = 131 - 53 = 78.

Step9: Eighth row ($^{26}$Mg)

Atomic number of Mg (magnesium) from periodic table is 12. So number of protons = 12, number of electrons = 12, mass number is 26, number of neutrons = 26 - 12 = 14.

Step10: Ninth row

Number of protons = 47, from periodic table the element is Ag (silver). Atomic number = 47, number of electrons = 46 (it is a Ag$^{+}$ ion), mass number = 47+(109 - 47)=109, number of neutrons = 109 - 47 = 62.

Symbol	Atomic Number	Mass Number	Number of Protons	Number of Electrons	Number of Neutrons
K	19	40	19	19	21
Sr	38	90	38	38	52
F	9	19	9	9	10
Ca$^{2 +}$	20	41	20	18	21
Sn	50	122	50	50	72
$^{131}$I	53	131	53	53	78
$^{26}$Mg	12	26	12	12	14
Ag$^{+}$	47	109	47	46	62

Answer:

Symbol	Atomic Number	Mass Number	Number of Protons	Number of Electrons	Number of Neutrons
K	19	40	19	19	21
Sr	38	90	38	38	52
F	9	19	9	9	10
Ca$^{2 +}$	20	41	20	18	21
Sn	50	122	50	50	72
$^{131}$I	53	131	53	53	78
$^{26}$Mg	12	26	12	12	14
Ag$^{+}$	47	109	47	46	62