Electrons in an Atom's Outermost Shell

The electron shell is the group of electrons surrounding the atom's nucleus. The atom's chemical properties are determined by these electrons.

About atoms

An atom is the smallest particle of matter. It is made up of a nucleus and electrons. The nucleus is the center of the atom and contains both protons, which carry a positive charge, and neutrons, which carry a neutral charge. The electrons, which are negatively charged, surround the nucleus. They are held in place by an electromagnetic force.

About electrons

The negatively charged electrons do not circle around the nucleus of the atom, as had once been pictures. Instead, they form a type of spinning orbit called an "electron cloud." Inside the cloud, the electrons can occupy various energized levels, or shells. An atom is called a stable atom when the number of protons, neutrons and electrons are equal. A stable atom has a neutral charge. Sometimes electrons travel in electron pairs, occupying the same shell level. In this case, one spins in the opposite way as the other, and makes the atom magnetically neutral. Each shell of the atom contains subshells, and each of these has at least one atomic orbital as well. An atom's shells are filled with different number of electrons. The s subshell can hold a maximum of two electrons. The next subshell, p, can hold up to six. The d subshell holds up to 10 and the f up to 14. The g subshell can contain as many as 18 electrons before it is filled. The outer shell of any atom is the one farthest from the nucleus. Free electrons can occur in the outermost shell as well. Because of their distance from the nucleus, these electrons can have a weak bond to the atom and wander. An example of this is found in the atoms of copper.

The outermost shell of an atom

The atom's outermost shell is called the valence shell. The electrons in this location are known as valence electrons. Valence electrons have the highest energy in the atom. They are also the most reactive. The inner electrons, by comparison, are not usually part of the chemical reactions of the atom. If an element has the same number of electrons in its shell, it tends to have the came chemical properties as other elements with this configuration. The design of the periodic table displays this. The periodic table organizes and displays the elements according to the number of valence electrons, or electrons in the outer shell. For instance, elements in group 1, known as the alkali metals, have one valence electron. These include lithium, sodium potassium, rubidium caesium, francium and ununennium. These metals have common traits, such as softness and low density, low melting and boiling points. A covalent bond is created when atoms share their valence electrons. This is most common in atoms with one electron in their outer shell.

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