8.5 ABCD Chem. Pre-Assessment

Which of the following best describes an electron?

• It has no charge and about the same mass as a proton.
• It has a negative charge and much less mass than a proton. 
• It has a positive charge and much more mass than a neutron.
• It has a negative charge and about the same mass as a neutron. 

An atom has 25 protons, 30 neutrons, and 25 electrons.  What is the charge of the atom's nucleus?

• +25
• +30
• -25
• -30

A model of beryllium atom is shown above.  What types of particles are found in the cloud surrounding the atom's nucleus? 

• Positively charged particles and negatively charged protons
• Negatively charged particles only
• Neutral particles and positively charged particles
• Positively charged particles only

The table below lists three characteristics of an atom of an element.  
Number of Protons:  37
Number of Neutrons:  48
Number of Valence Electrons:  1
An atom of which element is described by the data in the table?

• Radon (Rn)
• Cadmium (Cd)
• Rubidium (Rb)
• Astatine (At)

A model of an atom is shown above.  An atom of which element is represented by this model?

• Boron (B)
• Carbon (C)
• Neon (Ne)
• Sodium (Na)

When trying to identify an unknown element, a scientist determines what other elements the unknown element reacts with chemically.  Which property of the unknown element determines the other elements it reacts with?

• The total number of neutrons in the unknown element.
• The total number of particles in the nucleus of the unknown element
• The number of protons in the nucleus of the unknown element
• The number of valence electrons in the unknown element

Which two elements on the periodic table are in the same period?

• Sn and Rb
• F and Cl
• K and Ba
• Se and Te

• 1
• 2
• 3
• 4

• Atom 1 and Atom 2
• Atom 1 and Atom 4
• Atom 2 and Atom 3
• Atom 3 and Atom 4

In which of these compounds are there twice as many ocygen atoms as hydrogen atoms?

• H₃PO₄
• H₂SO₄
• HCIO₃
• H₂O