PSc Atomic Structure CFA

Which of the following elements is a member of the halogen family and is in period 3?

• Argon (Ar)
• Bromine (Br)
• Chlorine (Cl)
• Sulfur (S)

What is the atomic mass for silicon?

• 14.0
• 14.1
• 28.1
• 42.2

Which of the following is the most important factor in determining an element's place in the periodic table?

• number of protons
• number of neutrons
• atomic charge
• atomic density

Oxygen has an atomic number of 8. Which of the following elements would you expect to be most similar to oxygen in terms of its chemical properties?

• nitrogen (N)
• fluorine (F)
• sulfur (S)
• chlorine (Cl)

The table below shows the atomic mass of four stable calcium (Ca) isotopes.  What characteristic is different in each isotope?

• the position in the periodic table of the elements
•   the net charge of the nucleus
• the mass of the protons in the nucleus
• the number of neutrons in the nucleus

Which of the following has six valence electrons?

• magnesium (Mg)
• Silicon (Si)
• sulfur (S)
• argon (Ar)

Which statement best describes the density of an atom's nucleus?

• The nucleus occupies most of the atom's volume but contains little of its mass.
• The nucleus occupies very little of the atom's volume and contains little of its mass.
• The nucleus occupies most of the atom's volume and contains most of its mass.
• The nucleus occupies very little of the atom's volume but contains most of its mass.

Which of the following is the same for both hydrogen (H) and potassium (K)?

• atomic mass
• total mass of neutrons
• number of valence electrons
• number of filled energy levels

What does it mean when an atom is said to be neutral?

• It's atomic number is the same as its mass.
• It has the same number of protons and electrons.
• It has the same number of protons and neutrons.
• The amount of neutrons is equal to the atomic number.

Which drawing best describes the part that is shown by the arrow?

• It is an electron, and it has a negative charge.
• It is an electron, and it has a positive charge.
• It is a proton, and it has a negative charge.
• It is a proton, and it has a positive charge.