Matter & Change
Mass
A measure of the amount of matter that an object contains.
energy levels
The specific energies an electrons can have in an atom or other system
atomic radius
one half of the distance between the nuclei of two atoms of the same element when the atoms are joined
molecule
a neutral group of atoms joined together by covalent bonds
atom
The smallest particle of an element that retains its identity in a chemical reaction.
Volume
A measure of the space occupied by a sample of matter
Quantum
The amount of energy needed to move an electron from one energy level to another.
main group metals
metallic elements in groups 1A through 7A of the periodic table
What does a molecular formula show?
How many atoms of each element a substace contains
electrons
A negatively charged subatomic particle
physical properties
A quality or condition of a substance that can be observed or measured without changing the substance composition
spin
A quantum mechanical property of electrons that may be thought of as clockwise or counter clockwise
Noble gases
An element in group 8A of the periodic table
Covalent bond
How many atoms of each element a substace contains
atomic number
The number of protons in the nucleus of an atom of an element.
a substance produced in a chemical reaction
product
Who proposed that an electron is found only in specific circular paths, or orbits, around the nucleus?
Bohr
non-metals in group 7A of the periodic table
Halogens
What does it mean to be “monatomic”?
When elements exist as only one atom
What can we use to observe individual atoms?
scanning electron microscopes.
a change that produces matter with a different composition than the original matter.
chemical change
The arrangement of electrons of an atom in its ground state into various orbitals around the nuclei of atoms
Electron configurations
one of group B elements in in which the highest occupied s sublevel and a nearby d sublevel generally contains electrons
transition metals
what are many molecular compounds at room temperature
liquids and gases
Name the three kinds of subatomic particles.
electrons, protons, and neutrons