Question

1. complete the following table. you do not need to fill in the darkened boxes.

isotope format atomic # mass # # of protons # of neutrons # of electrons charge atom or ion?
6 c 8
6 12 6 18 +2
6 -1
20 35 0
35 22 18 -2
40 18 8 10
40 ar 18
16 o - 2

Explanation:

Step1: Recall atomic - related concepts

Atomic number = number of protons. Mass number = number of protons+number of neutrons. Charge = number of protons - number of electrons. An atom has a charge of 0, and an ion has a non - zero charge.

Step2: First row

Atomic number = 6, so number of protons = 6. Mass number= number of protons + number of neutrons. Given number of neutrons = 8, so mass number = 6 + 8=14. Charge = number of protons - number of electrons. Let the number of electrons be $x$. Since it's not given as an ion, assume charge = 0, so $6−x = 0$, then $x = 6$. It is an atom.

Step3: Second row

Atomic number = 6, number of protons = 6. Mass number = 12. Number of neutrons=mass number - number of protons = 12 - 6 = 6. Charge = + 2, so number of protons - number of electrons=+2. Let number of electrons be $y$, then $6 - y=2$, so $y = 4$. It is an ion.

Step4: Third row

Atomic number = 20, number of protons = 20. Mass number = 40. Number of neutrons=mass number - number of protons = 40 - 20 = 20. Charge = 0, so number of protons - number of electrons = 0. Let number of electrons be $z$, then $20 - z=0$, so $z = 20$. It is an atom.

Step5: Fourth row

Atomic number = 35, number of protons = 35. Mass number = 57. Number of neutrons=mass number - number of protons = 57 - 35 = 22. Charge=-2, so number of protons - number of electrons=-2. Let number of electrons be $w$, then $35 - w=-2$, so $w = 37$. It is an ion.

Step6: Fifth row

For $^{40}_{18}Ar$, atomic number = 18, number of protons = 18. Mass number = 40. Number of neutrons=mass number - number of protons = 40 - 18 = 22. Charge = 0, number of electrons = 18. It is an atom.

Step7: Sixth row

For $^{16}_{8}O^{2 - }$, atomic number = 8, number of protons = 8. Mass number = 16. Number of neutrons=mass number - number of protons = 16 - 8 = 8. Charge=-2, number of electrons = 10. It is an ion.

Isotope Format	Atomic #	Mass #	# of Protons	# of Neutrons	# of Electrons	Charge	Atom or Ion?
-	6	12	6	6	4	+2	Ion
-	20	40	20	20	20	0	Atom
-	35	57	35	22	37	-2	Ion
$^{40}_{18}Ar$	18	40	18	22	18	0	Atom
$^{16}_{8}O^{2 - }$	8	16	8	8	10	-2	Ion

Answer:

Isotope Format	Atomic #	Mass #	# of Protons	# of Neutrons	# of Electrons	Charge	Atom or Ion?
-	6	12	6	6	4	+2	Ion
-	20	40	20	20	20	0	Atom
-	35	57	35	22	37	-2	Ion
$^{40}_{18}Ar$	18	40	18	22	18	0	Atom
$^{16}_{8}O^{2 - }$	8	16	8	8	10	-2	Ion