Unit 3 Chemistry

Dalton's theory states that

• Atoms cannot be created, destroyed, or divided.

• atoms can be combined, rearranged, or separated in chemical reactions

• all matter is made of atoms

• all of these

Tags

NGSS.HS-PS1-7

Rutherford concluded that

• atoms were indivisible

• electrons formed the nucleus

• atoms were mostly empty space

• atoms had no charged particles

Boron has the atomic number 5 which means it has 5

• protons in the nucleus

• reactive nuclides

• neutrons in the cloud

• energy levels

Atoms of the same element have the same

• mass number

• atomic number

• number of neutrons

• atomic mass

One mole of krypton has

• 6.02 x 10²² atoms

• 6.02 x 10²³ atoms

• 5.02 x 10²² atoms

• 5.02 x 10²³ atoms

If the molar mass of nitrogen is 14 g, how many moles are in 62 g of nitrogen?

• 4.4 moles

• 8.68 moles

• 48 moles

• 7.6 moles

N can combine with O to make NO or NO₂. The ratio of masses of N that combine with a given mass of O is 1:2. This is

• Dalton's atomic theory

• law of conservation of mass

• law of definite proportions

• law of multiple proportions

Modern atomic theory states

• cathode rays are made of protons

• atoms cannot combine with any other atoms

• atoms can be divided in ordinary chemical reactions

• atoms of the same element may have different masses

Tags

NGSS.HS-PS1-7

The nucleus of an atom

• is very dense

• contains almost all the mass of the atom

• is positively charged

• all of these

Tags

NGSS.HS-PS1-8

As the mass number of an element's isotopes increases, the proton number

• decreases

• increases

• stays the same

• cannot be determined

Tags

NGSS.HS-PS1-8