An element’s or isotope’s atomic number tells how many protons are in its atoms. An element’s or isotope’s mass number tells how many protons and neutrons in its atoms .
What does the atomic mass tell you quizlet?
The atomic mass tells us the weight of protons and neutrons . ... The period number represents how many shells of electrons the atom has.
What can the atomic number tell you?
The atomic number uniquely identifies a chemical element . It is identical to the charge number of the nucleus. In an uncharged atom, the atomic number is also equal to the number of electrons. The sum of the atomic number Z and the number of neutrons N gives the mass number A of an atom.
What does the atomic mass help you find?
Atomic mass is the sum of the masses of the protons, neutrons, and electrons in an atom , or the average mass, in a group of atoms. However, electrons have so much less mass than protons and neutrons that they don’t factor into the calculation. So, the atomic mass is the sum of the masses of protons and neutrons.
Is atomic number and mass number the same?
An element’s mass number (A) is the sum of the number of protons and the number of neutrons. ... Protons and neutrons both weigh about one atomic mass unit or amu. Isotopes of the same element will have the same atomic number but different mass numbers.
What two particles have the same mass?
The two subatomic particles that have the same mass are protons and neutrons .
What does an atom’s group number help us determine?
group: A vertical column in the periodic table, which signifies the number of valence shell electrons in an element’s atom .
Where is atomic number located?
At the upper left is the atomic number, or number of protons. In the middle is the letter symbol for the element (e.g., H). Below is the relative atomic mass, as calculated for the isotopes found naturally on Earth.
Why isn’t the atomic mass a whole number?
Atomic mass is never an integer number for several reasons: The atomic mass reported on a periodic table is the weighted average of all the naturally occuring isotopes . Being an average it would be most unlikely to be a whole number. ... Only carbon-12 has a mass exactly equal to itself.
What is the formula to find atomic mass?
Calculating Average Atomic Mass
Average atomic mass = f 1 M 1 + f 2 M 2 +... + f n M n where f is the fraction representing the natural abundance of the isotope and M is the mass number (weight) of the isotope. The average atomic mass of an element can be found on the periodic table, typically under the elemental symbol.
What is an average atomic mass?
The atomic mass of an element is the average mass of the atoms of an element measured in atomic mass unit (amu, also known as daltons, D). The atomic mass is a weighted average of all of the isotopes of that element, in which the mass of each isotope is multiplied by the abundance of that particular isotope.
What is the difference between atomic weight and mass number?
Atomic mass is also known as atomic weight. Atomic mass is the weighted average mass of an atom of an element based on the relative natural abundance of that element’s isotopes. The mass number is a count of the total number of protons and neutrons in an atom’s nucleus.
What do you call the element from atomic number 57 71?
The elements from atomic number 57 to 71 are called Lanthanides . They are called lanthanides, since lanthanum is chemically identical to the elements in the sequence. ... The lanthanides are between Barium and Hafnium.
What is the difference between mass number and relative atomic mass?
The relative atomic mass is the mass reported for an element on the periodic table. It is based on samples of the element from different locations, which includes the different masses of the isotopes found in the samples. Mass number is the number of protons and neutrons in the atoms of specific isotopes.
Which has the smallest mass?
Of the three subatomic particles, the electron has the smallest mass. The mass of an electron is 1/1840 of an atomic mass unit (amu).
