Question

1. the total number of protons and neutrons in an atom is its
2. what is the mass number of a helium atom that has two protons and two

neutrons?

1. how many neutrons does a beryllium atom with four protons and a mass number of

nine have?

1. place the labels chemical symbol, atomic number, and mass number in the shorthand

notation below.

1. designate the atom shown in question 10 in the form

ame of element\-\mass
number.\

1. how many protons, neutrons, and electrons are in the atom discussed in questions 10

and 11? protons: neutrons: electrons:

isotopes (page 114 - 115)

1. how do atoms of neon - 20 and neon - 22 differ?

Explanation:

Step1: Mass number definition

The mass number of an atom is the sum of protons and neutrons. So for question 7, the answer is mass number.

Step2: Calculate mass number for helium

Given helium has 2 protons and 2 neutrons. Using the formula \(mass\ number=protons + neutrons\), we have \(2 + 2=4\). So for question 8, the mass number is 4.

Step3: Calculate neutrons for beryllium

Given beryllium has 4 protons and mass number 9. Using the formula \(neutrons=mass\ number - protons\), we have \(9 - 4 = 5\). So for question 9, the number of neutrons is 5.

Step4: Label shorthand notation

In the shorthand notation \(_{atomic\ number}^{mass\ number}element\ symbol\), for \(_{10}^{22}Ne\), the top - left number (22) is the mass number, the bottom - left number (10) is the atomic number, and \(Ne\) is the chemical symbol.

Step5: Designate atom

The atom in question 10 is neon with mass number 22, so it is designated as neon - 22.

Step6: Calculate protons, neutrons, electrons

• Protons: The atomic number is 10, so protons = 10.
• Neutrons: Using \(neutrons=mass\ number - protons\), \(22-10 = 12\).
• Electrons: In a neutral atom, electrons = protons, so electrons = 10.

Step7: Difference between neon - 20 and neon - 22

Neon - 20 has \(20-10=10\) neutrons and neon - 22 has \(22 - 10=12\) neutrons. They differ in the number of neutrons.

Answer:

1. mass number
2. 4
3. 5
4. Top - left: mass number; Bottom - left: atomic number; \(Ne\): chemical symbol
5. neon - 22
6. Protons: 10; Neutrons: 12; Electrons: 10
7. They differ in the number of neutrons. Neon - 20 has 10 neutrons and neon - 22 has 12 neutrons.