Atomic Structure
Which subatomic particle determines the atomic number of an element?
An atom has the same number of protons and electrons. Is it neutral or an ion?
neutral
An element has two isotopes:
X-20 = 80%
X-22 = 20%
Would its average atomic mass be closer to 20 amu or 22 amu?
20 amu
Which type of radiation is represented by α?
alpha particle
What subatomic particle helps provide stability to the nucleus
neutron
An atom has 17 protons and 18 electrons. What is its charge
1−
Two atoms have the same number of protons but different numbers of neutrons. What are they called?
isotopes
Element X has two isotopes:
X-10 = 25%
X-11 = 75%
Which isotope contributes more to the element's average atomic mass?
X-11
What is the charge of a beta particle?
−1
When balancing a nuclear equation, what two numbers must be conserved on both sides?
mass number and atomic number
An atom has 24 protons, 21 electrons, and 28 neutrons. Determine its:
A neutral fluorine atom gains one electron. What happens to its charge?
it becomes a 1− ion
An element has the following isotopes:
Isotope Mass & % Abundance
24.0 amu, 60%
25.0 amu, 30%
26.0 amu, 10%
Calculate its average atomic mass.
24.5 amu
Which of these has no charge?
Alpha
Beta
Gamma
gamma radiation
Complete the nuclear equation:
¹⁴₆C → ¹⁴₇N + _____
⁰₋₁e (beta particle)
An ion has a mass number of 39, 19 protons, and a 1+ charge. How many electrons and neutrons does it have?
18 electrons and 20 neutrons
Compare F and F⁻. What is different between these two atoms? Be Specific!
their number of electrons and their charge
F has 9 electrons and is neutral.
F⁻ has 10 electrons and a 1− charge.
An element has three isotopes:
Isotope Mass & % Abundance
27.98 amu, 92%
28.98 amu, 5%
29.97 amu, 3%
Without calculating, which isotope mass should the average atomic mass be closest to? Explain why.
27.98 amu, because it has by far the greatest relative abundance
Put these three types of radiation in order from least penetrating to most penetrating:
Gamma, Alpha, Beta
Alpha < Beta < Gamma
Complete the nuclear equation:
²³⁸₉₂U → ²³⁴₉₀Th + _____
⁴₂He (an alpha particle)
An unknown atom has 36 electrons, 44 neutrons, and a 1− charge. Identify the element and determine its atomic number and mass number.
bromine (Br), atomic number 35, mass number 79
Particle A has 12 protons, 12 neutrons, and 12 electrons.
Particle B has 12 protons, 13 neutrons, and 10 electrons.
Give two ways these particles differ.
An element has two main isotopes: X-10 and X-11. Its average atomic mass is 10.81 amu.
Which isotope is more abundant, and how can you tell?
X-11
The average atomic mass of 10.81 amu is much closer to 11 than to 10, indicating that X-11 is more abundant.
Identify the type of radiation:
alpha particle
Complete the nuclear equation and identify the type of radiation emitted:
²¹⁰₈₄Po → _____ + ⁴₂He
²⁰⁶₈₂Pb; alpha radiation