Atoms

Question 1

In light of the nuclear model for the atom, which statement is true about isotopes.

Answer 1

• For a given element, the size of an atom is the same for all of the element’s isotopes.
• All atoms of a given element do not have the same mass.

Question 2

John Daltons atomic theory and it’s flaw.

Answer 2

• Each element is composed of tiny, indestructible particles called atoms.
• All atoms of a given element are identical in mass and properties (Note: isotopes were discovered later)
• Atoms combine in simple, whole-number ratios to form compounds.
• In a chemical reaction, atoms only change the way that they are bound together with other atoms. (atoms retain their identity)

NOTE: Atoms were falsely believed to be indivisible which was refrained by the discovery of sub-atomic particles.

Question 3

Lavoisier’s Experiment’s conclusion.

Answer 3

“Matter is neither created nor destroyed but only

changed in form by combination or loss of a substance”

Question 4

• the law of definite proportions

Answer 4

All samples of a given compound, regardless of their source or how they were prepared, have the same proportions of their constituent elements (ex: 1.2 pg. 43)

Question 5

• The law of multiple proportions (By John Dalton):

Answer 5

When two elements (call them 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 (ex: 1.2 pg. 44)

Question 6

Densities of solids and liquids are usually experessed as.

Densities of gases are expressed as.

Answer 6

g/mL

g/L