February 17, 2011 #3

Today in class, we reviewed atoms and subatomic particles again.

We reviewed that:

• atoms are made of smaller particles.
• those particles are called subatomic particles.
• there are three different types of subatomic particles: protons, neutrons, and electrons

We also did a PhET Simulation called Build an Atom and used it to answer six questions. The Build an Atom simulation was a simulation where we added and took away different subatomic particles to determine what element the atom was, whether it was an ion, what the atomic mass was, whether it was unstable or stable, what charge it was, and how it looked on the periodic table.

These were the questions that we needed to answer:

+ What do these particles do? (charges)

The protons and electrons determine the charge of the atom. If there are more protons than electrons in an atom, the charge is positive. If there are more electrons than protons, the charge is negative. If there is the same amount of protons and electrons, the charge is neutral.

+What controls an element's identity?

The number of protons determine the element's identity.

+What controls the atomic mass of an atom?

The mass of the protons and neutrons determine the atomic mass of the atoms.

+What is an Ion? An Isotope?

An ion is a negatively or positively charged atom. An isotope is an atom with an irregular number of neutrons.

+What does all of the numbers and letters refer to in each periodic table box?

The number in the top left corner of the box is the atomic mass of the atom. The number in the bottom left corner is the number of protons in the atom. The letter in the middle of the box determines what element the atom is going to be. The number in the top right corner of the box whether atom is positively charged or negatively charged and how many particles make it positive or negative.

We used the simulation and previous notes to answer these questions, but I am still confused what makes an atom stable or unstable.

-CS