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How to Represent Electrons in an Energy Level Diagram

Chemists sometimes use an energy level diagram to represent electrons when they’re looking at chemical reactions and bonding. An energy level diagram is more useful and easier to work with than quantum [more…]

How to Depict Electrons in Electron Configuration Notation

Chemists use electron configuration notation to depict electrons in chemical reactions and bonding. Electron configuration notation is easier to use than the quantum mechanical model. [more…]

Why Are Valence Electrons Important?

Valence electrons are the electrons in the outermost energy level of an atom — in the energy level that is farthest away from the nucleus. When chemists study chemical reactions, they study the transfer [more…]

Isotopes: Different Types of Atoms

Atoms in a chemical element that have different numbers of neutrons than protons and electrons are called isotopes. The atoms in a particular element have an identical number of protons and electrons but [more…]

Ions: Atoms with an Electrical Charge

Atoms (or groups of atoms) in which there are unequal numbers of protons and electrons are called ions. Usually, the number of protons and electrons in atoms are equal. But there are cases in which an [more…]

The Periodic Table: Families and Periods

In the periodic table of elements, there are seven horizontal rows of elements called periods. The vertical columns of elements are called groups, or families [more…]

Radioactivity and Man-Made Radioactive Decay

Radioactivity is the spontaneous decay of an unstable nucleus. An unstable nucleus may break apart into two or more other particles with the release of some energy. This breaking apart can occur in a number [more…]

The Process of Natural Radioactive Decay

Certain naturally occurring radioactive isotopes are unstable: Their nucleus breaks apart, undergoing nuclear decay. Sometimes the product of that nuclear decay is unstable itself and undergoes nuclear [more…]

Nuclear Chemistry: Half-Lives and Radioactive Dating

Scientists look at half-life decay rates of radioactive isotopes to estimate when a particular atom might decay. A useful application of half-lives is [more…]

The Basics of Nuclear Fission

Nuclear fission occurs when a larger isotope breaks apart into two or more elements. Scientists usually accomplish this task (for some controlled nuclear reactions) by bombarding a large isotope with a [more…]

Nuclear Fusion: The Hope for Our Energy Future

Nuclear fusion is essentially the opposite of nuclear fission. In fission, a heavy nucleus is split into smaller nuclei. With fusion, lighter nuclei are fused into a heavier nucleus. [more…]

What Are the Effects of Radiation and Radon?

Radiation can destroy tissue and ionize and fragment cells. Radon is a radioactive isotope that has been linked to increased instances of lung cancer. Radon-222 is formed naturally as part of the decay [more…]

Ionic Bonds: Why and How Ions Are Formed

Ionic bonding is the type of bonding that holds salts together. To better understand why and how ions — atoms that have a charge due to the loss or gain of electrons — are formed, you can study what happens [more…]

Positive and Negative Ions: Cations and Anions

Cations (positively-charged ions) and anions(negatively-charged ions) are formed when a metal loses electrons, and a nonmetal gains those electrons. The electrostatic attraction between the positives and [more…]

Polyatomic Ions: Names and Symbols

Many ions are monoatomic, which means that they are composed of just one atom. However, ions can also be polyatomic, composed of a group of atoms.

For example, take a look at the following table. Notice [more…]

How to Decipher the Formulas of Ionic Compounds

When an ionic compound is formed, the cation and anion attract each other, resulting in a salt. An important thing to remember is that the compound must be neutral — have equal numbers of positive and [more…]

How Ionic Compounds Are Named

When you name ionic compounds, you write the name of the metal first and then the nonmetal. Suppose that you want to name the compound that results from the reaction of lithium and sulfur. You first write [more…]

How to Distinguish Electrolytes from Nonelectrolytes

Electrolytes are substances that conduct electricity in the molten state or when dissolved in water. Nonelectrolytes are substances that don’t conduct electricity when in these states. [more…]

Covalent Bonds: A Hydrogen Example

A covalent bond is a chemical bond that comes from the sharing of one or more electron pairs between two atoms. Hydrogen is an example of an extremely simple covalent compound. [more…]

Multiple Bonds in Covalent Bonding

Covalent bonding is the sharing of one or more electron pairs. In many covalent bonding situations, multiple chemical bonds exist — more than one electron pair is shared. [more…]

How to Name Binary Covalent Compounds

Binary covalent compounds are compounds made up of only two elements, such as carbon dioxide. Prefixes are used in the names of binary compounds to indicate the number of atoms of each nonmetal present [more…]

Covalent Bonds: Types of Chemical Formulas

There are several types of chemical formulas that you can use to represent chemical bonds. These include empirical formulas, molecular (or true) formulas, and structural formulas. [more…]

The Unusual Properties of Water Molecules

Water molecules have unusual chemical and physical properties. Water can exist in all three states of matter at the same time: liquid, gas, and solid.

Imagine that you’re sitting in your hot tub [more…]

Reactants and Products in Chemical Reactions

In a chemical reaction, substances (elements and/or compounds) called reactants are changed into other substances (compounds and/or elements) called products [more…]

Collision Theory: How Chemical Reactions Occur

In order for a chemical reaction to take place, the reactants must collide. The collision between the molecules in a chemical reaction provides the kinetic energy needed to break the necessary bonds so [more…]

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