Question

identify the missing information for each atom or ion. note that the atoms and ions are not necessarily neutral.

a se ion has a mass number of 77 and a charge of −2. determine the number of neutrons, protons, and electrons in this ion.

number of neutrons:

number of protons:

number of electrons:

an ion has a mass number of 65, 36 neutrons, and a charge of +1. identify the element symbol, and determine the number of protons and electrons in this ion.

element symbol:

number of protons:

number of electrons:

an atom or ion has 42 neutrons, 36 protons, and 36 electrons. identify the element symbol, and determine the mass number and charge for this atom or ion.

element symbol:

mass number:

charge:

Explanation:

First Part: Se ion

Step1: Find protons (Se atomic number)

Se has atomic number 34, so protons = 34.

Step2: Calculate neutrons (mass - protons)

Mass number = 77, so neutrons = \( 77 - 34 = 43 \).

Step3: Determine electrons (protons + charge magnitude, since charge = -2)

Electrons = \( 34 + 2 = 36 \).

Second Part: Ion with mass 65, neutrons 36, charge +1

Step1: Find protons (mass - neutrons)

Protons = \( 65 - 36 = 29 \) (element is Cu, atomic number 29).

Step2: Determine electrons (protons - charge, since charge = +1)

Electrons = \( 29 - 1 = 28 \).

Third Part: Atom/ion with 42 neutrons, 36 protons, 36 electrons

Step1: Identify element (protons = 36, element is Kr).

Step2: Calculate mass number (protons + neutrons)

Mass number = \( 36 + 42 = 78 \).

Step3: Determine charge (protons - electrons = \( 36 - 36 = 0 \)).

Answer:

s:

First Part:

number of neutrons: \( \boldsymbol{43} \)
number of protons: \( \boldsymbol{34} \)
number of electrons: \( \boldsymbol{36} \)

Second Part:

element symbol: \( \boldsymbol{Cu} \)
number of protons: \( \boldsymbol{29} \)
number of electrons: \( \boldsymbol{28} \)

Third Part:

element symbol: \( \boldsymbol{Kr} \)
mass number: \( \boldsymbol{78} \)
charge: \( \boldsymbol{0} \)