Unit 3 test Flashcards
isotopes
atoms of the same element with a different number of neutrons
ion
atom with charge (when the element symbols shows there is either -1, or +3)
anion
negatively charged ion (-2)
What is responsible for most of the mass of an atom and what is responsible for most of the volume of an atom?
nucleus is responsible for most mass and electron cloud is responsible for volume
cation
positively charged ion (+3)
democritus
first to go against belief and propose all matter was composed of indivisible particles he call “atomos”
democritus’s 3 core beliefs
- everything is composed of atoms which are physically indivisible
- atoms are indestructible and constantly moving
- there is empty space between atoms
who developed the law of definite proportions
proust in 1700s
the law of definite proportions
regardless of the amount used, a chemical compound is always composed of the same elements in the same proportions. elements combine in fixed proportions based on their mass
who came up with the law of conservation of matter
lavosier
the law of conservation of matter
in any chemical reaction the mass of the reactants always equals the total mass of the products
who developed the law of multiple proportions
dalton - also said there was more then one mass ratio
the law of multiple proportions
chemical compounds always contain the same proportions of elements by mass
Daltons atomic theory
1.all matter is composed of extremely small particles called atoms
2. atoms of a given element are identical. Atoms of different elements are different
3. atoms cannot be created, destroyed, or subdivided
4. atoms of different elements can combine in single whole number ratio
5. in chemical reactions, atoms are rearranged
john dalton
believed that an atom is like a solid ball
