• ## atomic number | Definition & Facts | Britannica

www.britannica.com/science/atomic-number Atomic number, the number of a chemical element in the periodic system, whereby the elements are arranged in order of increasing number of protons in the nucleus. Accordingly, the number of protons, which is always equal to the number of electrons in a neutral atom, is also the atomic number.
• ## Atomic number - Wikipedia

en.wikipedia.org/wiki/Atomic_number The atomic number or proton number (symbol Z) of a chemical element is the number of protons found in the nucleus of every atom of that element. The atomic number uniquely identifies a chemical element.It is identical to the charge number of the nucleus. In an uncharged atom, the atomic number is also equal to the number of electrons.. The sum of the atomic number Z and the number of neutrons ...
• ## Atomic number, atomic mass, and isotopes (article) | Khan ...

www.khanacademy.org/science/.../atomic-number-atomic-mass-and-isotopes-article Atomic number, atomic mass, and relative atomic mass Atoms of each element contain a characteristic number of protons. In fact, the number of protons determines what atom we are looking at (e.g., all atoms with six protons are carbon atoms); the number of protons in an atom is called the atomic number .
• ## What Is the Atomic Number? Definition and Importance

www.thoughtco.com/what-is-the-atomic-number-4031221 The atomic number of carbon is 6. More commonly, the isotope symbol already tells you the atomic number. For example, if the symbol is written as 14 6 C, the number "6" is listed. The atomic number is the smaller of the two numbers in the symbol. It is typically located as a subscript to the left of the element symbol.
• ## Atomic Number and Mass Number - nde-ed.org

www.nde-ed.org/EducationResources/HighSchool/.../atomicmassnumber.htm The atomic number of an element never changes, meaning that the number of protons in the nucleus of every atom in an element is always the same. What is an atom's mass number? All atoms have a mass number which is derived as follows. Review: An element's or isotope's atomic number tells how many protons are in its atoms.
• ## Atomic number | Definition of Atomic number at Dictionary.com

www.dictionary.com/browse/atomic-number Atomic number definition, the number of positive charges or protons in the nucleus of an atom of a given element, and therefore also the number of electrons normally surrounding the nucleus. Abbreviation: at. no.; Symbol: Z See more.
• ## Atomic number - definition of atomic number by The Free ...

www.thefreedictionary.com/atomic+number Define atomic number. atomic number synonyms, atomic number pronunciation, atomic number translation, English dictionary definition of atomic number. n. Symbol Z Abbr. at. no. The number of protons in an atomic nucleus. n the number of protons in the nucleus of an atom of an element. Abbreviation: at.
• ## Element List - Atomic Number, Element Name and Symbol

www.thoughtco.com/element-list-names-atomic-numbers-606529 Each element is identified by the number of protons in its atoms. This number is the atomic number. The periodic table lists the elements in order of increasing atomic number. Each element has a symbol, which is one or two letters. The first letter is always capitalized. If there is a second letter, it is lowercase.
• ## Atomic Number | Encyclopedia.com

www.encyclopedia.com/science-and-technology/chemistry/.../atomic-number Atomic number Atomic number is defined as the number of protons in the nucleus of an atom . This concept was historically important because it provided a theoretical basis for the periodic law. Dmitri Mendeleev's discovery of the periodic law in the late 1860s was a remarkable accomplishment.
• ## What is an Atomic Number? (with pictures)

www.wisegeek.com/what-is-an-atomic-number.htm The atomic number is the number of protons — positively charged particles — in the nucleus an atom of a chemical element. Elements are distinguished from one another by the numbers of these particles they have, and so each element has its own unique atomic number.