Question
(C.6D) Relative abundance and atomic mass of the naturally occurring isotopes of hafnium:
5% - 176 amu
19% - 177 amu
27% - 178 amu
14% - 179 amu
35% - 180 amu
What is the average atomic mass of hafnium?
Group of answer choices
180 amu
177 amu
179 amu
176 amu
Flag question: Question 3
Question 31 pts
(C.6B) Neils Bohr published his model of the atomic structure in 1913. He introduced the theory of electrons traveling in orbits around the atom's nucleus, with electrons orbiting only in certain orbits called shells. Each shell can contain a fixed number of electrons.
According to this model of the atom, the chemical properties of an element are mainly determined by
Group of answer choices
the number of electrons in the outer shell.
the total number of electrons in all shells.
the difference between number of electrons and protons
the number of electrons in the inner shells.
Flag question: Question 4
Question 41 pts
(C.6B) Which pair below describes isotopes of the same element?
Group of answer choices
an atom with 8 protons and 8 neutrons - an atom with 7 protons and 8 neutrons
an atom with 6 protons and 8 neutrons - an atom with 8 protons and 6 neutrons
an atom with 7 protons and 6 neutrons - an atom with 6 protons and 6 neutrons
an atom with 6 protons and 6 neutrons - an atom with 6 protons and 7 neutrons
5% - 176 amu
19% - 177 amu
27% - 178 amu
14% - 179 amu
35% - 180 amu
What is the average atomic mass of hafnium?
Group of answer choices
180 amu
177 amu
179 amu
176 amu
Flag question: Question 3
Question 31 pts
(C.6B) Neils Bohr published his model of the atomic structure in 1913. He introduced the theory of electrons traveling in orbits around the atom's nucleus, with electrons orbiting only in certain orbits called shells. Each shell can contain a fixed number of electrons.
According to this model of the atom, the chemical properties of an element are mainly determined by
Group of answer choices
the number of electrons in the outer shell.
the total number of electrons in all shells.
the difference between number of electrons and protons
the number of electrons in the inner shells.
Flag question: Question 4
Question 41 pts
(C.6B) Which pair below describes isotopes of the same element?
Group of answer choices
an atom with 8 protons and 8 neutrons - an atom with 7 protons and 8 neutrons
an atom with 6 protons and 8 neutrons - an atom with 8 protons and 6 neutrons
an atom with 7 protons and 6 neutrons - an atom with 6 protons and 6 neutrons
an atom with 6 protons and 6 neutrons - an atom with 6 protons and 7 neutrons
Answers
GPT-4o mini
Let's break down each question one by one:
### Question 1: Average Atomic Mass of Hafnium
To calculate the average atomic mass of hafnium using the relative abundances and atomic masses of its isotopes, you multiply the fractional abundance of each isotope by its atomic mass and then sum these values up.
Here's the calculation:
- \( (0.05 \times 176) + (0.19 \times 177) + (0.27 \times 178) + (0.14 \times 179) + (0.35 \times 180) \)
Calculating each term:
- \( 0.05 \times 176 = 8.8 \)
- \( 0.19 \times 177 = 33.63 \)
- \( 0.27 \times 178 = 48.06 \)
- \( 0.14 \times 179 = 25.06 \)
- \( 0.35 \times 180 = 63.00 \)
Now sum these values:
- \( 8.8 + 33.63 + 48.06 + 25.06 + 63.00 = 178.55 \)
So, the average atomic mass of hafnium is approximately **179 amu**.
### Question 2: Neils Bohr's Model of Atomic Structure
According to Niels Bohr's model, the chemical properties of an element are mainly determined by:
- **the number of electrons in the outer shell.**
This is correct because the electrons in the outer shell (also known as valence electrons) are primarily responsible for an element's reactivity and bonding behavior.
### Question 3: Identifying Isotopes
Isotopes are atoms of the same element that have the same number of protons but different numbers of neutrons.
From the provided options, the correct pair is:
- **an atom with 6 protons and 6 neutrons - an atom with 6 protons and 7 neutrons.**
This pair describes isotopes of the same element (carbon in this case), differing in their neutron count.
### Summary of Answers:
1. Average atomic mass of hafnium: **179 amu**
2. Chemical properties determined by: **the number of electrons in the outer shell.**
3. Isotopes of the same element: **an atom with 6 protons and 6 neutrons - an atom with 6 protons and 7 neutrons.**
### Question 1: Average Atomic Mass of Hafnium
To calculate the average atomic mass of hafnium using the relative abundances and atomic masses of its isotopes, you multiply the fractional abundance of each isotope by its atomic mass and then sum these values up.
Here's the calculation:
- \( (0.05 \times 176) + (0.19 \times 177) + (0.27 \times 178) + (0.14 \times 179) + (0.35 \times 180) \)
Calculating each term:
- \( 0.05 \times 176 = 8.8 \)
- \( 0.19 \times 177 = 33.63 \)
- \( 0.27 \times 178 = 48.06 \)
- \( 0.14 \times 179 = 25.06 \)
- \( 0.35 \times 180 = 63.00 \)
Now sum these values:
- \( 8.8 + 33.63 + 48.06 + 25.06 + 63.00 = 178.55 \)
So, the average atomic mass of hafnium is approximately **179 amu**.
### Question 2: Neils Bohr's Model of Atomic Structure
According to Niels Bohr's model, the chemical properties of an element are mainly determined by:
- **the number of electrons in the outer shell.**
This is correct because the electrons in the outer shell (also known as valence electrons) are primarily responsible for an element's reactivity and bonding behavior.
### Question 3: Identifying Isotopes
Isotopes are atoms of the same element that have the same number of protons but different numbers of neutrons.
From the provided options, the correct pair is:
- **an atom with 6 protons and 6 neutrons - an atom with 6 protons and 7 neutrons.**
This pair describes isotopes of the same element (carbon in this case), differing in their neutron count.
### Summary of Answers:
1. Average atomic mass of hafnium: **179 amu**
2. Chemical properties determined by: **the number of electrons in the outer shell.**
3. Isotopes of the same element: **an atom with 6 protons and 6 neutrons - an atom with 6 protons and 7 neutrons.**