Unit 3 Test- Atomic Structure

The mass number of an element that has18 protons, 18 electrons, and 19 neutrons is _____.

• 12.5
• 13
• 25
• 37

The atomic number of an element that has 9 protons, 9 electrons, and 10 neutrons is _____.

• 9
• 10
• 19
• 28

Tags

NGSS.MS-PS1-1

Carbon-12 has 98.2% abundance, carbon-13 has 1.7% abundance, and carbon-14 has 0.1% abundance.  Which isotope contributes most to the average atomic mass?

• Carbon-12
• Carbon-13
• Carbon-14
• They all contribute equally

Which particle contributes least to the total mass of an  atom?

• Proton
• Neutron
• Electron
• Nucleus

Atomic Number:  26
Neutrons:  30
Electrons:  25

• Normal Atom
• Isotope
• Anion
• Cation

Which statement about subatomic particles is true?

• Protons, neutrons, and electrons all have about the same mass.
• Unlike protons or neutrons, electrons have no mass.
• Neutrons have no charge and no mass.
• An electron has far less mass than either a proton or neutron.

Which of the following is unique for any given element?

• the number of neutrons
• the charge on the electrons
• the number of protons
• the mass of a neutron

The mass number of a single atom  is

• the sum of the protons and neutrons in the atom.
• twice the number of protons in one atom of the element.
• a ratio based on the mass of a carbon-12 atom.
• a weighted average of the masses of the element’s isotopes.

Tags

NGSS.HS-PS1-8

The dense center region of an atom

• electron cloud
• core
• nucleus
• centrino

Tags

NGSS.HS-PS1-8

Changing the number of neutrons in an atom changes its...

• element type.

• mass.

• charge.

• atom type.

Tags

NGSS.HS-PS1-8