Atomic Structure Flashcards
What is a atom?
The smallest particle of an element that consists of electrons surrounding a nucleus that contains protons and neutrons
What is a molecule?
The smallest particle of an element or compound that can exist independently. Molecules are formed when atoms join together by chemical bonds.
What is the structure of an atom?
Atoms are made up of subatomic particles called protons, neutrons and electrons.
The nucleus is composed of protons and neutrons and the electrons orbit around the nucleus in different shells.
Particle, relative charge, relative mass
Proton +1 1
Neutron 0 1
Electron -1 1/1836
What is atomic mass?
The the number of protons in the nucleus of an atom.
What is a mass number?
The sum of the number of protons and neutrons in the nucleus of an atom.
What are isotopes?
Atoms of the same element that contains the same number of protons and electrons but a different number of neutrons. Therefore, they have the same atomic number but a different mass number.
What was the relative atomic mass (Ar)?
Weighted average mass of one atom of an element, taking into account the abundances of all the isotopes of that element. It is measured as a ratio to 1/12 of the mass of an atom of carbon-12.
What is the equation for isotopes?
(% of isotope 1 x mass of isotope 1) + (% of isotope 2 x mass of isotope 2)
Ar = _____________________________
100
What is the isotope example of Rubidium?
Isotope Number of protons Number of neutrons Percentage of isotope in sample
1 37 48 72%
2 37 50 28%
Use information from the table to calculate the relative atomic mass of this sample of Rubidium. Give your answer to one decimal place.
( 72 x 85 ) + ( 28 x 87 )
\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_ = 85.6
100
Relative atomic mass = 85.6
