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Learning Objective

1. Atomic Number 112
2. Atomic Number 117
3. Atomic Number 11 Element
4. Atomic Element 11
5. Elements With Atomic Number 11

Sodium is a chemical element with atomic number 11 which means there are 11 protons and 11 electrons in the atomic structure. The chemical symbol for Sodium is Na. Sodium is a soft, silvery-white, highly reactive metal. In chemistry and atomic physics, an electron shell may be thought of as an orbit followed by electrons around an atom's nucleus.The closest shell to the nucleus is called the '1 shell' (also called the 'K shell'), followed by the '2 shell' (or 'L shell'), then the '3 shell' (or 'M shell'), and so on farther and farther from the nucleus. Isotopes of the same element will have the same atomic number but different mass numbers. Atomic number, chemical symbol, and mass number. Carbon has an atomic number of six, and two stable isotopes with mass numbers of twelve and thirteen, respectively. Its average atomic mass is 12.11. Scientists determine the atomic mass by calculating the. Here are all the possible meanings and translations of the word atomic number 11. Princeton's WordNet (0.00 / 0 votes)Rate this definition: sodium, Na, atomic number 11 (noun).

• Determine the relationship between the mass number of an atom, its atomic number, its atomic mass, and its number of subatomic particles

Key Points

• Neutral atoms of each element contain an equal number of protons and electrons.
• The number of protons determines an element’s atomic number and is used to distinguish one element from another.
• The number of neutrons is variable, resulting in isotopes, which are different forms of the same atom that vary only in the number of neutrons they possess.
• Together, the number of protons and the number of neutrons determine an element’s mass number.
• Since an element’s isotopes have slightly different mass numbers, the atomic mass is calculated by obtaining the mean of the mass numbers for its isotopes.

Terms

• atomic massThe average mass of an atom, taking into account all its naturally occurring isotopes.
• mass numberThe sum of the number of protons and the number of neutrons in an atom.
• atomic numberThe number of protons in an atom.

Atomic Number

Neutral atoms of an element contain an equal number of protons and electrons. The number of protons determines an element’s atomic number (Z) and distinguishes one element from another. For example, carbon’s atomic number (Z) is 6 because it has 6 protons. The number of neutrons can vary to produce isotopes, which are atoms of the same element that have different numbers of neutrons. The number of electrons can also be different in atoms of the same element, thus producing ions (charged atoms). For instance, iron, Fe, can exist in its neutral state, or in the +2 and +3 ionic states.

Mass Number

An element’s mass number (A) is the sum of the number of protons and the number of neutrons. The small contribution of mass from electrons is disregarded in calculating the mass number. This approximation of mass can be used to easily calculate how many neutrons an element has by simply subtracting the number of protons from the mass number. Protons and neutrons both weigh about one atomic mass unit or amu. Isotopes of the same element will have the same atomic number but different mass numbers.

Scientists determine the atomic mass by calculating the mean of the mass numbers for its naturally-occurring isotopes. Often, the resulting number contains a decimal. For example, the atomic mass of chlorine (Cl) is 35.45 amu because chlorine is composed of several isotopes, some (the majority) with an atomic mass of 35 amu (17 protons and 18 neutrons) and some with an atomic mass of 37 amu (17 protons and 20 neutrons).

Given an atomic number (Z) and mass number (A), you can find the number of protons, neutrons, and electrons in a neutral atom. For example, a lithium atom (Z=3, A=7 amu) contains three protons (found from Z), three electrons (as the number of protons is equal to the number of electrons in an atom), and four neutrons (7 – 3 = 4).

Show Sources

Boundless vets and curates high-quality, openly licensed content from around the Internet. This particular resource used the following sources:

http://www.boundless.com/
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http://en.wiktionary.org/wiki/atomic_number
Wiktionary
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http://www.boundless.com//biology/definition/atomic-mass–2
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http://en.wikibooks.org/wiki/A-level_Chemistry/OCR/Atoms,_Bonds_and_Groups/Atoms_and_Reactions/Atoms
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http://cnx.org/content/m44390/latest/?collection=col11448/latest
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The Element Sodium

[Click for Isotope Data]

Atomic Number 112

Atomic Number: 11

Atomic Weight: 22.98976928

Melting Point: 370.95 K (97.80°C or 208.04°F)

Boiling Point: 1156 K (883°C or 1621°F)

Density: 0.97 grams per cubic centimeter

Phase at Room Temperature: Solid

Element Classification: Metal

Atomic Number 117

Period Number: 3

Group Number: 1

Group Name: Alkali Metal

What's in a name? From the English word soda and from the Medieval Latin word sodanum, which means 'headache remedy.' Sodium's chemical symbol comes from the Latin word for sodium carbonate, natrium.

Say what? Sodium is pronounced as SO-dee-em.

History and Uses:

Although sodium is the sixth most abundant element on earth and comprises about 2.6% of the earth's crust, it is a very reactive element and is never found free in nature. Pure sodium was first isolated by Sir Humphry Davy in 1807 through the electrolysis of caustic soda (NaOH). Since sodium can ignite on contact with water, it must be stored in a moisture free environment.

Sodium is used in the production of titanium, sodamide, sodium cyanide, sodium peroxide, and sodium hydride. Liquid sodium has been used as a coolant for nuclear reactors. Sodium vapor is used in streetlights and produces a brilliant yellow light.

Sodium also forms many useful compounds. Some of the most common are: table salt (NaCl), soda ash (Na₂CO₃), baking soda (NaHCO₃), caustic soda (NaOH), Chile saltpeter (NaNO₃) and borax (Na₂B₄O₇·10H₂O).

Estimated Crustal Abundance: 2.36×10⁴ milligrams per kilogram

Estimated Oceanic Abundance: 1.08×10⁴ milligrams per liter

Atomic Number 11 Element

Number of Stable Isotopes: 1 (View all isotope data)

Ionization Energy: 5.139 eV

Oxidation States: +1

Atomic Element 11

Electron Shell Configuration:	1s2
2s2 2p6
3s1

Elements With Atomic Number 11

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