8.5 A,B, and C chemistry

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

Which of these best describes one of the subatomic particles that could be found at location X in the model of an atom shown above?

• It has mass but no charge.
• It has no mass and a positive charge. 
• It has a large mass and a negative charge.
• It has no mass and an equal number of positive and negative charges.

An atom of a certain element has 36 protons, 36 electrons, and a mass number of 84. At room temperature this element is a very stable gas. How many neutrons are in this atom?

• 120
• 50
• 48
• 0

If an atom has six positively charged subatomic particles, which of the following must it also have in order to become a neutral atom?

• Twelve protons
• Six neutrons
• Three electrons
• Six electrons

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)

Which of the above models of an atom represents a reactive metal?

• A
• B
• C
• D

Which of the above models of an atom represents a stable atom that will no react?

• A
• B
• C
• D

The atoms of a certain element each contain 9 protons and 7 valence electrons. Which statement correctly identifies this element and describes its' chemical reactivity?

• The element is lithium, and it is highly reactive.
• The element is fluorine, and it is not very reactive
• The element is lithium, and it is not very reactive.
• The element is fluorine, and it is highly reactive.

The model of the periodic table above shows the locations of four elements.  A student is asked to identify an element that is a pale-yellow brittle solid and does not conduct electricity. At which location in this periodic table would the element most likely be found?

• 1
• 2
• 3
• 4