Matter cannot be broken down into small particles. He called it atomos (atomos, indivisible)

became the foundation of the three basic laws in chemical changes

States that matter neither created nor destroyed during an ordinary chemical change

States that a given compound always shows a fixed proportion

An atom is a sphere of uniformly distributed positive charge with electrons attached to it Or a positively charged sphere with electrons inside it

The nucleus is very small compared to the total volume of the atom The electrons are found outside the nucleus

Proposed a model like a miniature solar system This model shows that electrons are moving in definite energy levels

States that when two elements combine to form 2 more different compounds, and the amount of one element is constant

Model conceives of electrons as undulations of matter, that is, it describes the wave behaviour of the electron

is a qualitative test in analytical chemistry used to help identify the composition of sample

electron jumpes to a higher shell

electron returns to lower shell

the way in which electrons are arranged around the nuclei of atoms

electrons enter orbitals of the lowest energy level first. Electrons will successively occupy available orbitals in order of increasing energy

no electrons in an atom can have the same quantum number, and the electrons occupying the same orbital must have an opposite spin.

When electrons enter a sublevel containing more than one orbital, they will spread out over the available orbitals with their spinds in the same direction before the pair with opposite spins

The set of numbers used to describe the position and nergy of the electron in an atom. Thhere are a total of four quantum numbers used to describe completely the movement and trajectories of each electron within an atom

It designates the direction of the electorn spin and may have a spin of +½ represented by (up arrow) or -½, represented (down arrow)

the number of values of the orbital angular number l can also be used to identify the number subshells in a

is an interval ranging from -1 to +1 (so it can be be zero a negative integer or a positive integer) Determines the number of orbitals and their orientation within a subshell