Unit 2 Chemistry: Atoms Unit Test

The total number of protons and neutrons in the nucleus of an atom is its

• Atomic number
• Avogadro's number
• Mass number
• Average atomic mass

Which is the smallest part of an element that retains all of the properties of the element?

• Proton
• Neutron
• Electron
• Atom

A newly discovered element, Novium (Nv), has three naturally occurring isotopes. Nv-110 has a mass of 109.9843 amu and a percent abundance of 80.12%. Nv-112 has a mass of 111.9991 amu and a percent abundance of 18.45%. Nv-115 has a mass of 114.9987 amu and a percent abundance of 1.43%. What is the average atomic mass of Novium?

• 111.2 amu

• 110.5 amu

• 112.0 amu

• 113.7 amu

Rowen is studying chemistry and discovers an atom that has 17 protons, 17 electrons, and 19 neutrons. What is the mass of the element Rowan found?

• 34

• 36

• 53

• 35.45

Which of the following is NOT a property of the atomic nucleus?

• It is composed of protons and neutrons

• It is extremely small compared to the whole atom

• It carries a positive charge

• It occupies most of the atom's space

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 number of protons and neutrons are equal.

Alex is studying different samples of the same element, but he notices that some samples have different masses. He wonders what determines the chemical identity of these samples, even though their masses differ. Which part of an atom would you advise Alex determines the identity of his element?

• The number of protons in the nucleus, because the atomic number is determined by the number of protons.

• The number of neutrons in the nucleus because the atomic number of an isotope is determined by the number of neutrons.

• The number of electrons surrounding the nucleus, because the charge on an atom is determined by the number of electrons.

• The number of protons and neutrons in the nucleus, because the atomic weight of an isotope is determined by the number of neutrons.

Which subatomic particle(s) have a mass close to 1 atomic mass unit (amu)?

• Electron

• Neutron

• Proton

• Quark

How many neutrons does an atom of Zinc-68 contain?

• 30 neutrons.

• 38 neutrons.

• 40 neutrons.

• 68 neutrons.

Brayden is studying different isotopes of the element Titanium in he science class. As he examines isotopes with increasing mass numbers, he notices that the number of protons ​ (a)  

• decreases

• increases

• stays the same

• doubles each time the mass number increases