Unit 2 Test: Atomic Theory and Structure

The nucleus of an atom is

• Negatively charged and has a low density.

• Negatively charged and has a high density.

• Positively charged and has a low density.

• Positively charged and has a high density.

• None of these

An atom of an element with atomic number 48 and mass number 120 contains

• 48 protons, 48 electrons, and 72 neutrons

• 72 protons, 48 electrons, and 48 neutrons

• 120 protons, 48 electrons, and 72 neutrons

• 72 protons, 72 electrons, and 48 neutrons

Which of these statements is not true?

• Atoms of the same element can have different masses

• The nucleus of an atom has a positive charge

• Atoms of isotopes of an element have different numbers of protons

• Atoms are mostly empty space

What is the Element Symbol, Number of protons, Number of neutrons, and Charge on Atom

If the Atomic Number: 51, Mass Number: 122, # of electrons: 54

• Element Symbol: Sb,

  # of protons: 51,

  # of neutrons: 71,

  charge on atom: -3

• Element Symbol: Lu,

  # of protons: 51,

  # of neutrons: 71,

  charge on atom: -3

• Element Symbol: Sb,

  # of protons: 52,

  # of neutrons: 68,

  charge on atom: +3

• Element Symbol: Xe

  # of protons: 54,

  # of neutrons: 68,

  charge on atom: 0

How many neutrons are there in Pb-206? Pb-207?

• Pb-206: 124, Pb-207: 125

• Pb-206: 122, Pb-207: 123

• Pb-206: 126, Pb-207: 127

• Pb-206: 128, Pb-207: 129

How can you determine the number of neutrons in an atom if you know its atomic number and mass number?

• Subtract the atomic number from the mass number

• Add the atomic number to the mass number

• Multiply the atomic number by the mass number

• Divide the mass number by the atomic number

What is the charge of a proton?

• Negative

• Positive

• Neutral

• Variable

Which of the following is true about isotopes?

• They have different atomic numbers but the same mass number

• They have the same atomic number but different mass numbers

• They have different numbers of electrons but the same number of protons

• They are always ions

Which subatomic particle is not found in the nucleus of an atom?

• Proton

• Neutron

• Electron

• All of the above are found in the nucleus

This science discovered the electrons was a small negativity charged particle. He wrongly believed that the electron was found inside a hard dense sphere.