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Atom: Isotopes and Atomic Weight

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Wize University Chemistry Textbook > Atoms, Ions, & Isotopes

Isotopes and Atomic Weight

4 Activities

Wize University Chemistry Textbook > Atoms, Ions, & Isotopes

Atomic Structure

3 Activities

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Mark Yourself Question
  1. Grab a piece of paper and try this problem yourself.
  2. When you're done, check the "I have answered this question" box below.
  3. View the solution and report whether you got it right or wrong.
An ion with a -2 charge has a mass number of 52 and contains 26 electrons. Which element is this ion? Specify the isotope as well.
More Isotopes and Atomic Weight Questions:
Practice: Isotopes
An atom with 6 neutrons and a mass number of 13 is an isotope of which element?
Elements: Isotopes
Bromine is a noxious fuming red liquid in its elemental form. Naturally occurring bromine has two stable isotopes 79Br (78.918u) and 81Br (80.916u). What are the relative abundances of these two isotopes?
Enter your answer as a percentage (ex. If the answer is 16.26%, enter 16.26 as the answer)
The natural abundance of Bromine is 79.904 g/mol
Elements: Isotopes
Bromine is a noxious fuming red liquid in its elemental form. Naturally occurring bromine has two stable isotopes 79Br (78.918u) and 81Br (80.916u). What are the relative abundances of these two isotopes?
Enter your answer as a percentage (ex. If the answer is 16.26%, enter 16.26 as the answer)
Elements: Isotopes
Bromine is a noxious fuming red liquid in its elemental form. Naturally occurring bromine has two stable isotopes 79Br (78.918u) and 81Br (80.916u). What are the relative abundances of these two isotopes?
Enter your answer as a percentage (ex. If the answer is 16.26%, enter 16.26 as the answer)
Elements: Isotopic Mass
Fe has three isotopes in relatively high abundance.
54Fe 53.94 amu 5.8 % rel. abundance
56Fe 55.94 amu 91.8 % rel. abundance
Practice: Isotopes
An atom with 6 neutrons and a mass number of 13 is an isotope of which element?
Mg has three isotopes. 24Mg is the most abundant (78.70%). Calculate the percentages of the other two isotopes. The exact masses are given below:
24Mg = 23.98504 u
25Mg = 24.98584 u
The Atom
2. Calculate the average mass of chlorine to two decimal places given its two isotopes: chlorine-35 (34.97 amu, 76% abundance) and chlorine-37 (36.97 amu, 24% abundance).
The Atom
Calculate the average mass of chlorine to three decimal places given its two isotopes: bromine-79 (78.918 amu, 51% abundance) and bromine-81 (80.916 amu, 49% abundance).
Elements: Isotopes and Atomic Mass
Hydrogen exists as two naturally occurring isotopes 1H (1.00782504u) (99.9885%) and deuterium, 2H. What is the atomic mass of deuterium? The atomic mass of hydrogen is 1.00794u.
Elements: Isotopes
Bromine is a noxious fuming red liquid in its elemental form. Naturally occurring bromine has two stable isotopes 79Br (78.918u) and 81Br (80.916u). What are the relative abundances of these two isotopes?
Enter your answer as a percentage (ex. If the answer is 16.26%, enter 16.26 as the answer)
Elements: Isotopes
Nitrogen has two naturally occurring isotopes, nitrogen-14 (14.003074008u) and nitrogen-15 (15.0001088982). What is the percent abundance of each isotope if the standard atomic weight of nitrogen is 14.0067?
Elements: Isotopes
The transition metal rhenium has two stable isotopes. The atomic mass of rhenium is 186.2 g/mol. Given that 37.1% of natural rhenium is Re-185, what is the other stable isotope?
If the abundance of 6Li (6.015121 amu) is 7.500% and the abundance of 7Li (7.016003 amu) is 92.500%, what is the average atomic mass?
Boron has an average atomic mass of 10.81 amu. It has 2 isotopes: 11B (relative abundance 80 %) and 10B (relative abundance 20 %). If 11B has an atomic mass of 11.01 amu, how much does 10B weigh in amu?
Chlorine has two isotopes of interest. One has an atomic mass of 34.97 amu (relative abundance 75 %), while the other make up the remaining 25 % of this element. If Cl has an average atomic mass of 35.47 amu, what is the mass of the second isotope in amu?
B has two isotopes that are available naturally in meaningful abundance. 10B (10.01 g/mol) has a relative abundance of 20 %, while 11B (11.01 g/mol) has a relative abundance of 80 %. If you are given a 12 g sample, how many moles of 10B are in the sample (answer in mol)?
Elements: Isotopic Mass
Copper exists as two naturally occurring isotopes 63Cu (62.92960) (69.17%) and 65Cu. What is the atomic mass of 65Cu?
Elements: Isotopic Mass
Fe has three isotopes in relatively high abundance.
54Fe 53.94 amu 5.8 % rel. abundance
56Fe 55.94 amu 91.8 % rel. abundance
How would you determine the number of neutrons in an atom? Let's say the element is F.
Atom: Isotopes
Selenium has a number of isotopes associated with it.
76Se = 75.92 amu rel. abundance = 0.094
77Se = 76.92 amu rel. abundance = 0.076
Atom: Determining the mass
What is the total mass of a C atom?
Given the following information:
"The Periodic Table", image retrieved from Chemistry 2e (https://d3bxy9euw4e147.cloudfront.net/oscms-prodcms/media/documents/Chemistry2e-OP_QCzV58S.pdf) by Flowers, P et al., is licensed under CC BY.
Carbon is made up of two stable isotopes, 12C and 13C. 12C is the most abundant form (98.93%) with 13C making up the remaining 1.07%. The 12C nuclei is defined as exactly 12 amu, what is the weight of the 13C nuclei? For this problem use the precise atomic weight of carbon, 12.0107
Elements: Calculating Isotopic Abundances
There are two naturally occurring and stable isotopes of lithium, 6Li (6.0151 amu) and 7Li (7.0160 amu). What is the abundance of 7Li in naturally occurring Lithium?
Atom: Calculating the Mass of One Isotope
Naturally occurring potassium contains two stable isotopes. The lighter isotope, 39K ( 38.9637 amu) is the more abundant isotope, accounting for 93.26% of the nuclei. What is the weight of the heavier isotope, 41K?
Boron (atomic weight 10.81) is made up of two stable isotopes, 11B and 10B. The boron-11 nuclei weighs 11.0093 amu and the boron-10 nuclei weighs 10.0129 amu. The percentage of 11B and 10B in naturally occurring boron respectively is,
How many protons does 13C have?
An atom with 6 neutrons and a mass number of 13 is an isotope of which element?
How many electrons are there in 2759CO3+?^{59}_{27}CO^{3+}?
Elements: Isotopes
Which of the following species has an isotope with a mass number of 42, 18 electrons, and an overall charge of 2+?
More Atomic Structure Questions:
Atomic Structure
Complete the following blanks in the table. Elements can be neutral atoms or charged ions. You may use the Periodic Table provided.
Bohr model: Energy
In a Hydrogen atom, for a transition to occur from n = 3 to n = 2, would energy need to be absorbed or emitted?
The Atom
1. Match the following definitions with the correct term.
The Atom
For germanium-73 (charge = 3+), there are
32
protons,
41
neutrons and
29
electrons.
The Atom
3. For zinc-65 (charge = 2+), there are
30
protons,
35
neutrons and
28
electrons.
Atom: Nuclear Notation
Nuclear Notation - Practice Question
How many protons, neutrons and electrons are there in 75As3-?
Answer: There are
33
protons,
42
neutrons and
36
electrons.
Elements: Atomic vs Mass Number
An atom contains 11 protons and 12 neutrons in its nucleus. Which of the following statements is/are correct?
(i) This atom has an atomic number of 12. (ii) Its mass number is 23. (iii) This atom has 12 electrons.
Elements: Atomic Number
Each element in the periodic table is assigned a number called the atomic number. This is equal to:
How many protons (p), neutrons (n) and electrons (e) are present in 80200Hg2+{\small _{80}^{200}Hg^{2+}}?
Of the following, which contains the greatest amount of neutrons?
How many protons does 12C have?
Match the subatomic particle to its mass and charge.
An element is known to have a mass number of 27.
"The Periodic Table", image retrieved from Chemistry 2e (https://d3bxy9euw4e147.cloudfront.net/oscms-prodcms/media/documents/Chemistry2e-OP_QCzV58S.pdf) by Flowers, P et al., is licensed under CC BY.
Elements: Atomic Mass
What is the total mass of a CO molecule? Given the following:
"The Periodic Table", image retrieved from Chemistry 2e (https://d3bxy9euw4e147.cloudfront.net/oscms-prodcms/media/documents/Chemistry2e-OP_QCzV58S.pdf) by Flowers, P et al., is licensed under CC BY.
The symbol for mass number is A)
A
. The symbol for atomic number is B)
Z
(Note: Use upper case letters)
A subatomic particle has a mass of 0.00054858 amu. Which particle is it?
Oxygen has a mass number of 16 amu. How many electrons does it have?
Definitions
Connect the term with the definition
Atom: Atomic Structure and Weight
1) How many protons does 12C have?
2) How many neutrons does 57Fe have?
3) How many protons does 13C have?
How many protons, neutrons and electrons are in a 113In atom?
How many protons, neutrons and electrons are in a 90Sr atom?
How many protons, neutrons and electrons are in a 57Fe2+ cation?
Which of the following pairs of species are isoelectronic? (Select all that apply)
Atom: Number of Protons, Electrons, Neutrons
Number of Protons, Electrons, & Neutrons
Example:
How many protons, electrons, and neutrons does Sr2+ have?
How many neutrons does 57Fe have?
How many protons does 13C have?
Atomic structure: Practice
Complete the following blanks in the table. Elements can be neutral atoms or charged ions. You may use the Periodic Table provided.
Elements: Isotopes
Which of the following species has an isotope with a mass number of 42, 18 electrons, and an overall charge of 2+?
Atomic Structure: Practice
Complete the following blanks in the table. Elements can be neutral atoms or charged ions. You may use the Periodic Table provided.
CHEM 1011 (Dalhousie) - The Atom
Fill-out the table below (to input the atom/ion column, zinc-65 (charge = 2+), for example, would be inputted in the following format: Zn-65 (2+). If neutral, input: Zn-65).