2.1, 2.2, 2.3 Brownian Motion, Early Ideas, Modern Atomic Theory

2.1 Brownian Motion: Atoms Confirmed 2.2 Early Ideas about the Building Blocks of Matter

is not

Matter ______ (is/is not) infinitely divisible; dividing graphite into smaller and smaller pieces would eventually result in individual carbon atoms which cannot be divided to still have carbon.

atomos

Greek for indivisible

Brownian motion

explained by Einstein’s model, particle motion as a result of molecular bombardments of particles due to thermal energy of surrounding molecules

Scanning Tunneling Microscope (STM)

type of microscope which can form images of atoms themselves, or pick up and move individual atoms

atom

smallest identifiable unit of an element

law of conservation of mass

in a chemical reaction, matter is neither created nor destroyed

law of definite proprtions

aka law of definite composition, all samples of a given compound, regardless of their source or how they were prepared, have the same proportions of their constituent elements

the same compound

The law of definite proportions applies to two or more samples of ________________ (the same compound/different compounds).

law of multiple proportions

when two elements (A and B) form two different compounds, the masses of element B that combine with 1 g of element A can be expressed as a ratio of small whole numbers

different compounds

The law of multiple proportions applies to two ____________________ (of the same compound/different compounds) containing the same 2 elements A and B.

atomic theory

1. Each element is composed of tiny indestructible particles called atoms.

2. All atoms of a given element have the same mass and other properties that distinguish them from the atoms of other elements.

3. Atoms combine in simple, whole-number ratios to form compounds.

4. Atoms of one element cannot change into atoms of another element. In a chemical reaction, atoms only change the way they are bound together with other atoms.

atoms

atomic theory

1. Each element is composed of tiny indestructible particles called _____.

all

atomic theory

2. ___(no/some/all) atoms of a given element have the same mass and other properties that distinguish them from the atoms of other elements.

simple

atomic theory

3. Atoms combine in ______ (simple/complex) whole-number ratios to form compounds.

cannot

atomic theory

4. Atoms of one element ______ (can/cannot) change into atoms of another element. In a chemical reaction, atoms only change the way they are bound together with other atoms.