Grade

Dalton incorporated the law of conservation of mass into his atomic theory by asserting that

• atoms are indivisible.

• atoms of different elements have different properties.

• matter is composed of atoms.

• atoms can be destroyed in chemical reactions.

Tags

NGSS.HS-PS1-7

Oxygen can combine with carbon to form two compounds, carbon monoxide and carbon dioxide. The ratio of the masses of oxygen that combine with a given mass of carbon is 1:2. This is an example of

• the law of conservation of mass.

• Dalton's atomic theory.

• the law of conservation of energy.

• the law of multiple proportions.

Tags

NGSS.HS-PS1-7

If 63.5 g of copper (Cu) combine with 16 g of oxygen (O) to form the compound CuO, how many grams of oxygen will be needed to combine with the same amount of copper to form the compound CuO2?

• 16 g

• 32 g

• 64 g

• 127 g

Tags

NGSS.HS-PS1-7

Which concept in Dalton's atomic theory has been modified?

• All matter is composed of atoms.

• Atoms of different elements have different properties and masses.

• Atoms can combine in chemical reactions.

• Atoms cannot be divided.

A nuclear particle that has about the same mass as a proton, but with no electrical charge, is called a(n)

• nuclide.

• neutron.

• electron.

• isotope.

Tags

NGSS.HS-PS1-8

Protons within a nucleus are attracted to each other by

• the nuclear force.

• opposite charges.

• their energy levels.

• electron repulsion.

An atom is electrically neutral because

• neutrons balance the protons and electrons.

• nuclear forces stabilize the charges.

• the numbers of protons and electrons are equal.

• the numbers of protons and neutrons are equal.

The smallest unit of an element that can exist either alone or in combination with other such particles of the same or different elements is the

• electron.

• proton.

• neutron.

• atom.

Tags

NGSS.MS-PS1-1

Because a few alpha particles bounced back from the foil, Rutherford concluded that they were

• striking electrons.

• indivisible.

• repelled by densely packed regions of positive charge.

• magnetic.

Noble gases are generally

• semiconductors.

• malleable.

• brittle.

• unreactive.