Chemistry Assessment

Did Dalton believe that atoms could be created or destroyed?

• No

• Yes

Tags

NGSS.MS-PS1-5

According to Dalton's theory, all atoms of the same ______ are identical in size, mass, and other properties.

What is an atom?

• When a molecule has protons.

• A molecule at a molecular level.

• The building block of matter, smallest particles of an element.

• The basic unit for Chemistry.

Tags

NGSS.MS-PS1-1

Whose work did Thomson repeat and revise?

• Sir Isac Newton

• Sir William Crooks

What is the atomic number of an atom? Why is this number important?

• It shows the number of Neutrons in that element, it tells how much electrons the element has.

• It shows the number of Protons in that element, it tells how much electrons the element has.

Tags

NGSS.MS-PS1-1

A tin atom has an atomic number of 50 and a mass number of 118. How many neutrons are present in this atom?

• 68 Neutrons

• 168 Neutrons

Tags

NGSS.MS-PS1-1

What are isotopes?

• Isotopes are neutrons of the same element that are different by the number of electrons.

• Isotopes are Atoms of the same element that are different by the number of neutrons.

• Isotopes are protons of the same element that are different by the number of neutrons.

An isotope of yttrium has 39 protons and 59 neutrons. What is the mass number of that isotope?

• 98

• 20

An isotope with a mass number of 193 has 116 neutrons. What is the atomic number of this isotope?

• 307

• 77

Tags

NGSS.MS-PS1-1

An isotope of barium (atomic number 56) has an mass of 138. How many neutrons are in the nucleus of this isotope?

• 82 Neutrons

• 194 Neutrons