Elements

elements mixtures compounds how what why whereWhat is an element?

If elements can not be created by chemical reactions how are they formed?

How do metal elements appear in the Earths rocks, limestone and other geological features?

Below are quotes, information and explanations from standard science websites and articles explaining how elements were or are formed and their origin, according to Big Bang theory etc.
elements atoms ions how what why where

What are elements?

An element or chemical element is the simplest form of matter in that it cannot be further broken down using any chemical means. Yes, elements are made up of smaller particles, but you can't take an atom of an element and perform any chemical reaction that will break it apart or join its subunits to make a bigger atom of that element.
What Are Elements? | chemistry.about

elements structure periodic table explained

An element is a substance that is made entirely from one type of atom. For example, the element hydrogen is made from atoms containing a single proton and a single electron. If you change the number of protons an atom has, you change the type of element it is.

If you had very, very good eyes and could look at the atoms in a sample of hydrogen, you would notice that most of the hydrogen atoms would have no neutrons, some of them would have one neutron and a few of them would have two neutrons. These different versions of hydrogen are called isotopes. All isotopes of a particular element have the same number of protons, but have a different number of neutrons. If you change the number of neutrons an atom has, you make an isotope of that element.
What is an element? How many elements are there? | jlab.org

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An element is a type of matter composed of atoms that all have exactly the same positive charge on their nuclei. In other words, all atoms of an element have the same atomic number.
What is an element? | frostburg.edu

Same element but very different properties?

elements isotopes origin properties eu theory

How can you tell if two chemicals are the same element? Sometimes examples of a pure element look very different from each other. For example, diamond and graphite (pencil lead) are both examples of the element carbon. You wouldn't know it based on appearance or properties. However, atoms of diamond and graphite each share the same number of protons. The number of protons, particles in an atom's nucleus, determines the element.
What Are Elements? | chemistry.about

elements simple periodic table

Different kinds of atoms of the same element which have the same atomic number but different mass numbers or atomic masses (or atomic weights) are called isotopes of that element. As isotopes have the same atomic number, we may define it as "Atoms of the same element with same number of protons, but a different number of neutrons in their respective nuclei."

The isotopes of any element will have the same number of valence electrons or valency, resulting in identical chemical properties. The isotopes' physical properties are different mainly due to the neutron number variation, present in the nucleus. Properties such as melting point, boiling point, density etc., which depend upon the atomic mass should be different for different isotopes because the isotopes of an element have different masses.
Isotopes Definition and Characteristics of Isotopes | tutorvista.com

What are pure elements or mixtures and compounds?

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Pure elements contain atoms that all have the same number of protons. If the number of protons is mixed, you have a mixture or a compound.
What Are Elements? | chemistry.about

Atoms of different elements can join together in chemical reactions to form compounds. For example hydrogen and oxygen are elements. They react together to form water, a compound.
Compounds | bbc.co.uk

elements shells electrons electric universe theory

Single atoms - The atoms of some elements do not join up with other atoms. They stay as single atoms. The element helium is like this. Helium is an unreactive gas. Helium atoms do not join up with each other or any other element.
Single atoms - Atoms and molecules | bbc.co.uk

elements paried unpaired electrons

element - a basic substance that can't be simplified (hydrogen, oxygen, gold, etc)
atom - the smallest amount of an element
molecule - two or more atoms that are chemically joined together (H2, O2, H2O, etc)
compound - a molecule that contains more than one element (H2O, C6H12O6, etc)
What is the difference between atoms and elements? | jlab.org

elements

Carbon has 6 electrons, so it has 4 valence electrons, none of which are, or can be, paired. (Unless paired through chemical bonds, of course.) This means that carbon can connect many different ways: it can connect to 2 atoms through double bonds, 1 atom through a double bond and 2 atoms by basic bonds, 1 atom by a triple bond and 1 atom by a basic bond, and 4 atoms through basic bonds.
How many unpaired valence electrons are there in the carbon atom? | answers.com