Atoms - SC.8.P.8.7

(SC.8.P.8.7) The nucleus of an atom is the densest part of an atom. Why is the nucleus so dense?

• The nucleus is at the center of the atom.
• The nucleus contains all of the subatomic particles that have significant mass.
• The nucleus contains all of the positively charged particles in the atom.
• Electrons surround the nucleus.

(SC.8.P.8.7) Study the illustration of an atom shown below. How many electrons are found in this atom?

• 7
• 5
• 2
• 6

(SC.8.P.8.7) The total number of protons and neutrons in an atom determines its mass number. Some carbon atoms have a mass number of 13, and contain six protons. How many neutrons would this atom have in its nucleus?

• 13
• 19
• 7
• 6

(SC.8.P.8.7) Study the illustration below of an atom. Which two subatomic particles make up the nucleus of an atom?

• proton and electron
• neutron and proton
• electron and neutron
• ion and proton

(SC.8.P.8.7) Neutrally charged atoms have no net charge because they contain the same number of protons and electrons. What would happen to an atom if it were to lose one electron?

• The atom would then have a positive charge.
• The atom would then have a negative charge.
• The atom would still have no net charge.
• The atom would automatically also lose a proton from its nucleus.

(SC.8.P.8.7) Each element is identified by an atomic number. The atomic number indicates how many protons are found in one atom of that element. For example, calcium (Ca) has an atomic number of 20 as shown below. What is the net charge of the nucleus of this calcium atom?

• +20
• +1
• none
• +40

(SC.8.P.8.7) Atoms are composed of subatomic particles including protons, neutrons, and electrons. It takes more than 1,800 electrons to equal the mass of one proton. What can you conclude about the mass of an electron based on this fact?

• An electron’s mass is extremely small compared to a proton’s mass.
• An electron has the same mass as the nucleus.
• An electron’s mass is extremely large compared to a proton’s mass.
• An electron has the same mass as a neutron.

(SC.8.P.8.7) The diameter of an atom is about 100,000 times greater than the diameter of its nucleus. What can you conclude from this fact?

• The mass of an atom is related to its diameter.
• Most of the volume of an atom is found in its electron cloud.
• Most of the volume of an atom comes from protons and neutrons.
• The nucleus takes up most of the space in an atom.

(SC.8.P.8.7) While Elisa and Carmen were studying together for science class, Elisa created a drawing of an atom as shown below. Elisa decided to test Carmen’s knowledge of subatomic particles by asking her to fill in the missing label in her drawing. Which of the following should Carmen choose for the missing label?

• element
• neutron
• electron cloud
• isotope

(SC.8.P.8.7) According to atomic theory, elements are made up of small units. What is the name for the smallest unit of an element that can still be classified as that element?

• a molecule
• a mixture
• an atom
• a compound