Question 1

Shown here is a simplified representation of an atom: the smallest division of matter that may be isolated through physical or chemical methods.

Inside of each atom are several smaller bits of matter called particles. Identify the three different types of “elementary” particles inside an atom, their electrical properties, and their respective locations within the atom.


Question 2

Different types of atoms are distinguished by different numbers of elementary particles within them. Determine the numbers of elementary particles within each of these types of atoms:

• Carbon
• Hydrogen
• Helium
• Aluminum

Hint: look up each of these elements on a periodic table.


Question 3

Of the three types of elementary particles” constituting atoms, determine which type(s) influence the following properties of an element:

• The chemical identity of the atoms (whether it is an atom of nitrogen, iron, silver, or some other element).
• The mass of the atom.
• The electrical charge of the atom.
• Whether or not it is radioactive (spontaneous disintegration of the nucleus).


Question 4

The Greek word for amber (fossilized resin) is elektron. Explain how this came to be the word describing a certain type of subatomic particle (electron).


Question 5

It is much easier to electrically “charge” an atom than it is to alter its chemical identity (say, from lead into gold). What does this fact indicate about the relative mobility of the elementary particles within an atom?


Question 6

Early scientific researchers hypothesized that electricity was an invisible fluid that could move through certain substances. Those substances “porous” to this “fluid” were called conductors, while substances impervious to this “fluid” were called insulators.

We now know what electricity is composed of: tiny bits of matter, smaller than atoms. What name do we give these tiny bits of matter? How do these particles of matter relate to whole atoms?

In terms of these tiny particles, what is the difference between the atoms of conductive substances versus the atoms of insulating substances?


Question 7

Some of the particles comprising atoms react to each other in a way that scientists categorize as electric charge. There are two fundamental types of electric charge: positive and negative. Identify the respective charges of the following particles:

• Electrons
• Protons
• Neutrons

What would happen if you placed two electrons near each other in free space? Would they repel each other or attract each other? How about two protons? How about an electron and a proton? How about a neutron and a proton?


Question 8

Atoms are very, very small pieces of matter. This fact should go without saying, but it behooves us to be reminded of just how small atoms are. Chemists and physicists use a unit of measurement to represent quantities of different materials based on how many atoms (or molecules) there are in a particular sample. This unit of measurement is called the mole.

1 mole of pure iron metal weighs about 56 grams. Based on the definition of a mole, how many atoms of iron are in this 56 gram sample?


Question 9

How many atoms of iron are there in a sample measuring 2 ×103 moles? Determine the answer without using a calculator!


Question 10

Many students first learning about atomic structure and electricity notice a paradox with respect to the location of all the protons in an atom: despite their electrical charge, they are tightly bound together in a “core” called the nucleus. Based on what you know about electrical charges, explain why this is a paradox, and also what the solution to the paradox is.


Question 11

Write two algebraic equations relating the number of protons and neutrons in an atom to that atom’s atomic mass and atomic number:


P = Number of protons

N = Number of neutrons

A = Atomic mass

Z = Atomic number


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