Question

1. determine the following information from the atom symbols: protons? electrons? neutrons? mass #? atomic #? charge? atom, ion, or isotope? 42 20 ca 24 12 mg 2+ protons? electrons? neutrons? mass #? atomic #? charge? atom, ion, or isotope?

Explanation:

Step1: Recall atomic number rule

The atomic number (bottom - left number) is equal to the number of protons. For $_{20}^{42}Ca$, the atomic number is 20, so the number of protons is 20. For $_{12}^{24}Mg^{2 + }$, the atomic number is 12, so the number of protons is 12.

Step2: Determine electron number

In a neutral atom, the number of electrons equals the number of protons. For $_{20}^{42}Ca$ (neutral), the number of electrons is 20. For $_{12}^{24}Mg^{2+}$, it has lost 2 electrons, so the number of electrons is $12 - 2=10$.

Step3: Calculate neutron number

The mass number (top - left number) minus the atomic number gives the number of neutrons. For $_{20}^{42}Ca$, the number of neutrons is $42−20 = 22$. For $_{12}^{24}Mg^{2+}$, the number of neutrons is $24 - 12=12$.

Step4: Identify mass number

The mass number is the top - left number. For $_{20}^{42}Ca$, the mass number is 42. For $_{12}^{24}Mg^{2+}$, the mass number is 24.

Step5: Recall atomic number definition

The atomic number is the bottom - left number. For $_{20}^{42}Ca$, the atomic number is 20. For $_{12}^{24}Mg^{2+}$, the atomic number is 12.

Step6: Determine charge

$_{20}^{42}Ca$ is neutral, so the charge is 0. $_{12}^{24}Mg^{2+}$ has a charge of + 2.

Step7: Classify particle type

$_{20}^{42}Ca$ is an isotope (since the mass number is different from the most common form of calcium). $_{12}^{24}Mg^{2+}$ is an ion (because it has a non - zero charge).

Answer:

For $_{20}^{42}Ca$:
Protons: 20
Electrons: 20
Neutrons: 22
Mass #: 42
Atomic #: 20
Charge: 0
Atom, ion, or isotope: Isotope

For $_{12}^{24}Mg^{2+}$:
Protons: 12
Electrons: 10
Neutrons: 12
Mass #: 24
Atomic #: 12
Charge: + 2
Atom, ion, or isotope: Ion