Problem 22
Would isotopes of the same element have the same number of electrons?
Problem 22
A balloon contains helium gas. How are the helium atoms distributed in the balloon? Do the atoms move? If so, how? Copy the sketch above on your paper and draw the helium atoms inside it.
Problem 23
Compare and contrast protons, neutrons, and electrons.
Problem 23
If a sodium atom loses an electron and becomes a sodium ion with a charge of \(1+\), what would happen if a calcium atom loses two electrons?
Problem 24
You are told that an unknown liquid has a density of \(0.79 \mathrm{~g} / \mathrm{cm}^{3}\) and will not mix evenly with water. Predict what will happen if you pour some of this liquid into a glass of water, stir, and wait five minutes.
Problem 24
What is an isotope? Why are some isotopes useful to society?
Problem 25
What is the difference between chemical properties and physical properties? List one example of each type.
Problem 26
How is atomic number different from mass number?
Problem 26
Use the periodic table of the elements, located on the inside back cover, to classify the following substances as elements or compounds: iron, aluminum, carbon dioxide, gold, water, and sugar.
Problem 27
Explain what happens to water molecules when ice melts.
