Question

1. fill in the following chart. dont forget to come the isotope symbol for each atom or ion. example: ³²s⁻² element symbol atomic number mass number # of protons # of neutrons # of electrons ²⁰⁰hg 19 20 18 24 28 21 127 53 54 ³¹p⁻³ 38 88 36 79 118 79 ¹³⁷ba⁺²

Explanation:

Step1: Recall atomic number property

Atomic number = number of protons.

Step2: Recall mass - number formula

Mass number = number of protons+number of neutrons.

Step3: Determine electrons in ions

For neutral atoms, number of electrons = number of protons. For ions, adjust based on charge. A negative charge means extra electrons and a positive charge means fewer electrons.

For $^{200}Hg$:

• Atomic number of Hg is 80 (from periodic - table), so number of protons = 80.
• Mass number is 200. Number of neutrons = Mass number - number of protons = 200 - 80=120.
• For neutral Hg atom, number of electrons = 80.

For the ion with 19 protons:

• Atomic number = 19 (K, potassium).
• Mass number = number of protons+number of neutrons = 19 + 20=39.
• Since it has 18 electrons, it is a $K^{+}$ ion.

For the element with atomic number 24:

• Element is Cr (chromium).
• Mass number = number of protons+number of neutrons = 24 + 28 = 52.
• Since number of electrons = 21, it is a $Cr^{3 + }$ ion.

For the atom/ion with mass number 127 and 53 protons:

• Atomic number = 53 (I, iodine).
• Number of neutrons = Mass number - number of protons = 127 - 53 = 74.
• Since number of electrons = 54, it is an $I^{-}$ ion.

For $^{31}P^{-3}$:

• Atomic number of P is 15, so number of protons = 15.
• Mass number is 31. Number of neutrons = Mass number - number of protons = 31 - 15 = 16.
• Since it has a - 3 charge, number of electrons = 15+3 = 18.

For the element with atomic number 38:

• Element is Sr (strontium).
• Mass number is 88. Number of protons = 38. Number of neutrons = Mass number - number of protons = 88 - 38 = 50.
• Since number of electrons = 36, it is a $Sr^{2+}$ ion.

For the element with 79 protons:

• Atomic number = 79 (Au, gold).
• Mass number = number of protons+number of neutrons = 79+118 = 197.
• Since number of electrons = 79, it is a neutral Au atom.

For $^{137}Ba^{+2}$:

• Atomic number of Ba is 56, so number of protons = 56.
• Mass number is 137. Number of neutrons = Mass number - number of protons = 137 - 56 = 81.
• Since it has a + 2 charge, number of electrons = 56 - 2 = 54.

Element Symbol	Atomic number	Mass number	# of protons	# of neutrons	# of electrons
$^{39}K^{+}$	19	39	19	20	18
$^{52}Cr^{3+}$	24	52	24	28	21
$^{127}I^{-}$	53	127	53	74	54
$^{31}P^{-3}$	15	31	15	16	18
$^{88}Sr^{2+}$	38	88	38	50	36
$^{197}Au$	79	197	79	118	79
$^{137}Ba^{+2}$	56	137	56	81	54

Answer:

Element Symbol	Atomic number	Mass number	# of protons	# of neutrons	# of electrons
$^{39}K^{+}$	19	39	19	20	18
$^{52}Cr^{3+}$	24	52	24	28	21
$^{127}I^{-}$	53	127	53	74	54
$^{31}P^{-3}$	15	31	15	16	18
$^{88}Sr^{2+}$	38	88	38	50	36
$^{197}Au$	79	197	79	118	79
$^{137}Ba^{+2}$	56	137	56	81	54