Chemistry Chapter 4 Quiz
What is a mass number
The total number of protons and neutrons in an atom is called the mass number.
Each isotope of an element has
a fixed mass and a natural percent abundance.
An atomic mass unit (amu) is defined as
as one-twelfth of the mass of a carbon-12 atom
how do you calculate atomic mass or number in red?
atomic mass of isotope and relative abundance
How many protons, electrons, and neutrons are in each atom? a. 9, 4 Be b. 20, 10 Ne c. 23, 11 Na
atomic number = number of protons and electrons a. 4 b. 10 c. 11 a. number of neutrons = 9 - 4 = 5 b. number of neutrons = 20 - 10 = 10 c. number of neutrons = 23 - 11 = 12
What is subscript and what is superscript?
atomic number, and mass number
atomic number and mass number go where?
atomic on bottom and mass on top!
How do isotopes of an element differ?
different numbers of nuetrons
Which particle is negative
electron
The number of electrons must
equal the number of protons
Because isotopes of an element have different numbers of neutrons, they also have different
mass numbers.
Atoms are electrically
nuetral
Which particles is positive
proton
What is in the nucleus on an atom
protons and neutrons
A weighted average mass reflects both
the mass and the relative abundance of the isotopes as they occur in nature.
isotopes are chemically alike because (THIS IS IMPORTANT)
they have identical numbers of protons and electrons, which are the subatomic particles responsible for chemical behavior.
How do you calculate the atomic mass of an element?
to compare the relative masses of atoms using a reference isotope as a standard.
How many neutrons does oxygen have?
16-8 = 8
The element nitrogen (N) has an atomic number of 7. How many protons and electrons are in a neutral nitrogen atom?
7
What is an atomic number?
An element's atomic number is the number of protons in the nucleus of an atom of that element.
How are the atoms of one element different from the atoms of another element? How are isotopes of the same element different?
Atoms of different elements are different because they contain different numbers of protons. Isotopes of the same element are different because they have different numbers of neutrons, and thus different mass numbers.
The atomic mass of copper is 63.546 amu. Which of copper's two isotopes is more abundant: copper-63 or copper-65?
Copper-63!
Why are atoms with different numbers of neutrons still considered to be the same element?
Despite differences in the number of neutrons, isotopes are chemically alike. They have identical numbers of protons and electrons, which determine chemical behavior.
What makes one element different from another?
Elements are different because they contain different numbers of protons.
Isotopes
Isotopes are atoms that have the same number of protons but different numbers of neutrons.
How do you find the atoms composition
Number of neutrons = mass number - atomic number
atomic mass is a
The atomic mass of an element is a weighted average mass of the atoms in a naturally occurring sample of the element.
Why is the atomic mass of an element usually not a whole number?
The atomic mass of an element is usually not a whole number because it is a weighted average of the masses of the naturally occurring isotopes of the element.
What information is needed to determine the composition of a neutral atom of any element?
The atomic number and mass number are needed to determine an atom's composition. The atomic number gives the number of protons, which equals the number of electrons. The number of neutrons is the difference between the mass number and the atomic number.
