All Chapters
Ch.1 - Introduction to Biology
Ch.2 - Chemistry
Ch.3 - Water
Ch.4 - Carbon
Ch.5 - Biological Molecules
Ch.6 - Cells
Ch.7 - The Membrane
Ch.8 - Energy and Metabolism
Ch.9 - Respiration
Ch.10 - Photosynthesis
Ch.11 - Cell Signaling
Ch.12 - Cell Division
Ch.13 - Meiosis
Ch.14 - Mendelian Genetics
Ch.15 - Chromosomal Theory of Inheritance
Ch.16 - DNA Synthesis
Ch.17 - Gene Expression
Ch.18 - Regulation of Expression
Ch.19 - Viruses
Ch.20 - Biotechnology
Ch.21 - Genomics
Ch.22 - Development
Ch.23 - Evolution by Natural Selection
Ch.24 - Evolution of Populations
Ch.25 - Speciation
Ch.26 - History of Life on Earth
Ch.27 - Phylogeny
Ch.28 - Prokaryotes
Ch.29 - Protists
Ch.30 - Plants
Ch.31 - Fungi
Ch.32 - Overview of Animals
Ch.33 - Invertebrates
Ch.34 - Vertebrates
Ch.35 - Plant Anatomy
Ch.36 - Vascular Plant Transport
Ch.37 - Soil
Ch.38 - Plant Reproduction
Ch.39 - Plant Sensation and Response
Ch.40 - Animal Form and Function
Ch.41 - Digestive System
Ch.42 - Circulatory System
Ch.43 - Immune System
Ch.44 - Osmoregulation and Excretion
Ch.45 - Endocrine System
Ch.46 - Animal Reproduction
Ch.47 - Nervous System
Ch.48 - Sensory Systems
Ch.49 - Muscle Systems
Ch.50 - Ecology
Ch.51 - Animal Behavior
Ch.52 - Population Ecology
Ch.53 - Community Ecology
Ch.54 - Ecosystems
Ch.55 - Conservation Biology
Additional Practice
Atomic Structure

Practice: Oxygen

8 Protons             Atomic number: 

8 Neutrons          Mass number: 

8 Electrons          Atomic mass:

Practice: If oxygen has 9 electrons it will be a __________________________

Additional Problems
Organisms are composed of molecules, which are collections of smaller units, called a. molecules b. atoms c. electrons d. polymers e. ions
Negatively charged particles of atoms with almost no mass are called a. electrons b. protons c. neutrons d. ions e. polymers
When atoms gain or lose electrons, they become negatively or positively charged. They are known as a. molecules b. isotopes c. ions d. radioactive e. unstable atoms
A proton a. has one positive charge b. has one Dalton of mass c. is found in the nucleus of the atom d. only a and b are true e. a, b, and c are true
An electron a. has one negative charge b. has 1/1840 Dalton of mass c. is found in an area around the nucleus, called the orbital d. only a and b are true e. a, b, and c are true
The atomic number of an element is equal to the number of a. protons only b. neutrons only c. protons plus electrons d. protons plus neutrons e. neutrons plus electrons
Ordinary oxygen has an atomic mass number of 16 and an atomic number of 8. This means that the number of neutrons in this type of oxygen is a. 24 b. 8 c. 16 d. not stable e. none
Oxygen ordinarily has 8 protons and 8 neutrons. Another rare form has two extra neutrons. These two forms are a. oxygen ions b. oxygen isotopes c. oxygen compounds d. oxygen shells e. oxygen orbitals
Which of the following elements’ isotopic ratios are used to make absolute determinations of the time of formation of materials? a. oxygen b. hydrogen c. carbon d. nitrogen e. radon
The smallest chemical unit of an element is a molecule. a. True b. False
Atoms in which the number of electrons does not equal the number of protons are known as a. valences b. ions c. isotopes d. molecules e. orbitals
The area around a nucleus where an electron is most likely to be found is called a. electrical space b. an organelle c. polar space d. radioactive field e. an orbital
If a fluorine atom has an atomic weight of 16 and another has an atomic weight of 18 then these atoms are: a. enantiomers b. isotopes c. isomers d. radioactive e. unstable f. ions g. more than one of the above is correct
Ionizing radiation does NOT include:A. gamma raysB. UV raysC. X-raysD. cosmic rays