Student Exploration: Element Builder
Vocabulary: atom, atomic number, electron, electron dot diagram, element, energy level, ion, isotope, mass number, neutron, nucleus, periodic table, proton, radioactive, valence electrons
Prior Knowledge Questions (Do these BEFORE using the Gizmo.)
1. What are some of the different substances that make up a pizza? _____________________
2. What substances make up water? _____________________________________________
3. What substances make up an iron pot? _________________________________________
Elements are pure substances that are made up of one kind of atom. Pizza is not an element because it is a mixture of many substances. Water is a pure substance, but it contains two kinds of atom: oxygen and hydrogen. Iron is an element because it is composed of one kind of atom.
Atoms are tiny particles of matter that are made up of three particles: protons, neutrons, and electrons. The Element Builder Gizmo™ shows an atom with a single proton. The proton is located in the center of the atom, called the nucleus.
1. Use the arrow buttons ([pic]) to add protons, neutrons, and electrons to the atom. Press Play ([pic]).
A. Which particles are located in the nucleus?
B. Which particles orbit around the nucleus?
2. Turn on Show element name. What causes the element name to change? _____________ _________________________________________________________________________
|Activity A: |Get the Gizmo ready: |[pic] | | |Use the arrows to create an atom with two protons, two neutrons, and two electrons. | | |Subatomic particles |Turn on Show element name. | |
Question: What are the properties of protons, neutrons, and electrons?
1. Observe: Turn on Show element symbol and Element notation. Three numbers surround the element symbol: the mass number (A), electrical charge (no number is displayed if the atom is neutral), and the atomic number (Z).
2. Investigate: Watch how the numbers change as you add or remove particles.
A. Which number is equal to the number of protons in the atom? __________________
B. How can you calculate the number of neutrons (N) in an atom? _________________
C. Which particle (proton, neutron, or electron) has a positive charge? ______________
Negative charge? ______________No charge at all? ______________
3. Analyze: An isotope is an alternative form of an element. Each isotope of an element has the same number of protons, but a different number of neutrons. The isotope is represented by the atomic symbol and mass number, such as He-4. Some isotopes are stable, while others are radioactive, which means the atoms decay over time and emit radiation.
A. What are the stable isotopes of carbon? ___________________________________
B. What are the stable isotopes of nitrogen? __________________________________
C. List two radioactive isotopes of oxygen: ___________________________________
4. Practice: Use the Gizmo to answer the following questions.
A. How many electrons are in a neutral atom of lithium? ______
B. How many neutrons are in an atom of Mg-25? ______
C. What is the mass number of an atom with 5 protons and 7 neutrons? ______
D. When at atom is charged, it is called an ion. How many electrons are in O2-? ______