Chemistry Foundations: Atoms, Elements and Molecules

Questions and Answers

The equal number of protons and electrons

Elements

Chemical bond

Ions Signup and view all the answers

To measure the concentration of hydrogen ions in a solution Signup and view all the answers

Chemical reaction Signup and view all the answers

To catalyze specific chemical reactions Signup and view all the answers

Solution Signup and view all the answers

Study Notes

Matter is composed of atoms that contain protons and electrons.
Atoms have no electrical charge due to the equal number of protons and electrons.
There are over 100 different types of atoms, each with its own element.

Elements are the building blocks of matter and are essential for human nutrition.
Examples of nutrition-related elements include Hydrogen (H), Oxygen (O), Carbon (C), Nitrogen (N), Calcium (Ca), and Iron (Fe).

Molecules form when atoms interact and share electrons, forming a chemical bond.
Chemical formulas represent the number and type of atoms in a molecule.
Compounds are molecules that contain two or more different elements in specific proportions.
Solutions are evenly distributed mixtures of two or more compounds, with water often being the solvent.

Ions are atoms or groups of atoms that gain or lose electrons, resulting in an electrical charge.
Ions can be positively charged (e.g., ammonium ion) or negatively charged (e.g., hydroxide ion).
Electrolytes, such as sodium and potassium, are ions that conduct electricity and have important functions in the body.

Acids are substances that lose H+ when dissolved in water.
Bases are substances that remove and accept H+ when dissolved in water.
pH measures the concentration of hydrogen ions in a solution, with a pH of 7 being neutral.
The pH scale ranges from 0 to 14, with low values indicating high acidity and high values indicating high basicity.

Chemical reactions involve changes in the arrangement of atoms in molecules.
Synthetic reactions combine elements or compounds to form new substances.
Decomposition reactions break down molecules into smaller components.
Enzymes are molecules (usually proteins) that catalyze specific chemical reactions.

Enzymes speed up chemical reactions without becoming part of the products.
Enzymes have specific actions and are sensitive to environmental conditions such as pH, temperature, and presence of vitamins and minerals.
Examples of enzymes include sucrase, which breaks down sucrose into glucose and fructose.

Metabolism refers to the sum of all chemical reactions that occur in living cells.
Catabolic reactions involve breaking down molecules, while anabolic reactions involve synthesizing new compounds.