Atomic Structure Flashcards
What is an atom?
An atom is the smallest part of a substance that can exist, made of a nucleus and outer shells.
What are the subatomic particles in an atom?
Protons, Neutrons (found in the nucleus) and Electrons (orbit the nucleus in fixed shells).
How are the charges and masses of subatomic particles different?
Protons have a charge of +1 and mass of 1, Neutrons have no charge and mass of 1, Electrons have a charge of -1 and mass of 1/1800 (negligible).
How do you calculate the relative atomic mass (Ar) of an element?
Ar = (mass of isotope x % abundance) / 100.
What are isotopes?
Isotopes are atoms of the same element with the same protons and electrons, but different numbers of neutrons.
What is relative atomic mass (Ar)?
Relative atomic mass is the average mass of an element, taking into account all its isotopes, relative to a carbon-12 atom.
What is the relative formula mass (Mr)?
Mr is the sum of all relative atomic masses of the atoms shown in a formula/compound.
How do you calculate the relative formula mass?
Add up the relative atomic masses of all the atoms in the compound. Example: NaCl = (1x23) + (1x35.5) = 58.5.
What is electronic configuration?
Electronic configuration is the arrangement of electrons in shells around the nucleus. Shells fill from the inside out.
What are the maximum electron capacities of the first three shells?
1st shell: 2 electrons, 2nd shell: 8 electrons, 3rd shell: 8 electrons.
How do you determine the group number of an element?
The group number is the number of electrons in the outer shell.
How do you determine the period number of an element?
The period number is the number of electron shells.
