2.33 How Many Protons, Neutrons, and Electrons Are in Each of the Following?

2.33 How many protons, neutrons, and electrons are in each of the following?

(33.a) an oxygen atom with a mass number of 15

(33.b) a silver atom with a mass number of 109

(33.c) a chlorine atom with a mass number of 35

2.34 How many protons, neutrons, and electrons are in each of the following?

(34.a) a hydrogen atom with a mass number of 1

(34.b) a magnesium atom with a mass number of 26

(34.c) a lithium atom with a mass number of 6

2.35 What is the isotope symbol for atoms that contain the following numbers of subatomic particles?

(35.a) 1 proton, 1 electron, and 2 neutrons

(35.b) 4 protons, 4 electrons, and 5 neutrons

(35.c) 15 protons, 15 electrons, and 16 neutrons

2.36 What is the isotope symbol for atoms that contain the following numbers of subatomic particles?

(36.a) 2 protons and 1 neutron

(36.b) 47 protons and 62 neutrons

(36.c) 82 protons and 125 neutrons

2.40 What forms when a neutral atom undergoes each of the following changes?

(40.a) It gains one electron.

(40.b) It loses two electrons.

2.41 What forms when an ion with a 1+ charge undergoes each of the following changes? (41.a) It gains one electron.

(41.b) It loses two electrons.

2.52 Complete the following table for the designated ions.

Isotope Number of Number of Number of Symbol Protons Neutrons Electrons

81 − Br 35 38 50 36

1 + H 2.52 What element has 18 electrons when it forms an anion with a 2− charge?

2.53 What element has 27 electrons when it forms a cation with a 2+ charge?

2.54 What element has 46 electrons when it forms a cation with a 1+ charge? 2.55 An unknown element (X) discovered on a planet in another galaxy was found to exist as two isotopes. Their atomic masses and percent abundances are listed in the following table. What is the relative atomic mass of the element?

Isotope Mass (amu) Natural Abundance (%) 22 21.995 75.00 X 20 19.996 25.00 X 2.56 Suppose that the isotope abundance of magnesium on another planet has been determined to be different from that on Earth, as shown in the following table. Calculate the relative atomic mass of magnesium on this planet. Isotope Mass (amu) Natural Abundance (%) 24 23.985 20.00 Mg 25 24.985 20.00 Mg 26 25.983 60.00 Mg

2.81 Name the element that is an alkaline earth metal in period 5. 2.82 What element is in group IVB (4) and in period 4?

2.83 What element is in group IVA (14) and in period 2?

2.84 Identify each of the following elements as a metal, nonmetal, or metalloid.

(84.a) calcium

(84.b) carbon

(84.c) potassium

(84.d) silicon

2.85 For each element listed, write the symbol for the ion it forms.

(85.a) sodium

(85.b) oxygen

(85.c) sulfur

(85.d) chlorine

(85.e) bromine

2.86 For each element listed, write the symbol for the ion it forms.

(86.a) nitrogen

(86.b) phosphorus

(86.c) magnesium

(86.d) potassium

(86.e) aluminum