Test 1: Periodic Table, Atoms & Elements Flashcards
Atomic theory
the theory that all matter can be broken down to individual “fundamental pieces” which cannot be divided further
Matter can be divided into two types of pure substances
elements and compounds
Element
Matter that cannot be broken down into smaller substances (made from one type of atom)
The smallest unit of a compounds is a
molecule
Molecule
One or more types of atoms bonded together
4 fundamental assumptions laid out by John Dalton
- All matter is composed of atoms
- The atoms of a given element differ from the atoms of all other elements.
- Compounds are combinations of atoms; each molecule of the same compound has the same number and types of atoms.
- Atoms are not created or destroyed by chemical reactions.
All matter is composed of
Atoms
The atoms of a given element ___ from the atoms of all other elements.
differ
Compounds are
combinations of atoms; each molecule of the same compound has the same number and types of atoms
Atoms are not ___ by chemical reactions.
created or destroyed
Law of Constant Composition
The composition of pure substances always stays the same
Law of Conservation of Mass
Atoms are not created or destroyed by chemical reactions.
Both compounds and elements are considered __ substances
pure
How many known elements exist?
110
Every type of matter or substance on earth comes from
A distinct element or compound
Every element has been assigned a
Name and symbol
Atomic symbol
abbreviations for elements on the periodic table
Compounds contain whole number ratios of
atoms
We represent compounds (multiple elements) by
listing the symbol, followed by the quantity (amount present) of each element