The subatomic particles that make up atoms are protons, neutrons, and electrons. 2. Why do all isotopes of an element have the same chemical properties? In what way do isotopes of an element differ?
An isotope has the same number of protons but a different number of neutrons in the nucleus. 3. What is a covalent bond? An ionic bond?
An ionic bond is formed when one or more electrons are transferred from one atom to another. Covalent bond forms when electrons are shared between atoms. 4. What is a compound? How are compounds related to molecules?
Compound is a substance formed by the chemical combination of two or more elements in definite proportions. The molecules form the compounds and that’s how they are related. 5. How do van der Waals forces hold molecules together?
When oppositely charged region nearby molecule, they have forces that force them to hold together.
2-2 1. Use the structure of a water molecule to explain why it is polar.
A water molecule is polar because there is an uneven distribution of electrons between the oxygen and hydrogen atoms. 2. Compare acidic and basic solutions in terms of their H+ ions and OH- ion concentrations.
Acidic solutions contain higher concentrations of H+ ions than pure water and have pH values below 7. Basic, or alkaline, solutions contain lower concentrations of H+ ions than pure water and have pH values about 7. 3. What is the difference between a solution and a suspension?
Ions that gradually become dispersed in water is called solution, and suspension are mixtures of water and nondissolved material mixed together. 4. What does pH measure?
PH measures the concentration of H + ions in a solution.
2-3 1. Name four groups of organic compounds found in living things.
They are carbohydrates, lipids, nucleic acids, and proteins. 2. Describe at least one function of each group of organic compounds.
Lipids can store energy and are