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Chemistry Wonder World Q & A – 1. Matter, Molecules, Elements, Ions, Compounds
© Donald Reinhardt, Sept 12, 2013
 
We live in a material world of chemical things and chemistry. Chemistry as a science  helps us to understand ourselves and the world around us. Here we will explore the definitions and questions and answers of matter,elements, atoms, bonds, mixtures, solutions, pH, and chemical reactions.
Water Molecule. Diagram of Oxygen bonded to two hydrogen atoms. Note the atomic size differences between oxygen and hydrogen. Note also the position of the nucleus with protons and neutrons and the   outer band of electrons.

The Nature of the Universe and Our Planet

 Chemistry is elementary (basic and fundamental) and involves elements) and chemistry is embedded here on earth and in the stars. In the stars? Yes, the sun and other stars are primarily made up of two simple forms of matter.
Matter is anything that occupies space and has mass (weight is OK, but mass is a better term). So, back to the stars – what is the matter with them? The types of matter or chemical materials of our sun (and other stars) are the elements hydrogen and helium.  The sun and stars are ongoing thermonuclear reactions and these powerful reactions generate immense heat and light.
Thermo- means heat, and nuclear means the atoms nucleus, the nucleus of hydrogen. Remember that the heat and light of the sun is derived from reactions that are thermonuclear and these reactions directly affect the nuclei of hydrogen. This nuclear disturbance leads to the immense heat and light emitted by our earth's sun and all other stars.

What are elements?

Elements are the simplest, basic, different types of matter.
There are 92 naturally-occurring elements that have been discovered and another 20 elements that are man-made, i.e. produced artificially as a result of human experimentation and laboratory manipulation. Therefore, all known matter is of about 112 different types. All the elements are listed in the Periodic Table of Elements which we will discuss later.
Metals and non-metals are two major different types of elements.
What is an atom?  
An atom is the simplest and smallest form of an element that has all the properties of that element.
Atoms have a central nucleus which contains one or more protons and usually the same or a greater number of neutrons. Each and every proton has a positive charge and this is balanced by a negative charge of each electron which moves rapidly around the central nucleus. The neutron has no charge.
Since all atoms are balanced with an equal number of protons and electrons, they do not have a charge.  

What is the atomic mass or atomic weight?

Each proton and each neutron has a designated mass weight of 1.

The atomic mass is the combined number of all protons and neutrons in the nucleus of the atom. Remember this: the number of protons is defined by the designated atomic number. The atomic weight or mass is the number of protons and neutrons added together to give us the full, combined mass or weight value.
Examples of atomic mass: Hydrogen is 1 proton and 0 neutrons. Hydrogen has an atomic mass of 1. Oxygen has an atomic number of 8. Oxygen has 8 protons and also 8 neutrons, therefore  8 + 8 = 16 and this is the simple atomic mass of oxygen. Note this interesting fact: ordinary hydrogen usually only has 1 proton and no neutrons, but both deuterium and tritium which are isotopes of hydrogen have, respectively, 1 and 2 neutrons.

Isotopes – What are they?

An isotopes of an element is the same element which differs in atomic mass  (atomic weight).

This atomic mass difference is due to a difference in the number of neutrons among the isotopes of the same element.

Isotopes of the same element will differ always by atomic mass and some isotopes also may be radioactive and show decay of the nucleus with time.

Deuterium is hydrogen of atomic mass 2 (1 proton + 1 neutron) and tritium is a hydrogen isotope of mass 3 (1 proton and 2 neutrons). Tritium is radioactive.

What is an ion?

An ion is a charged atom that has either lost or gained one or more electrons and is therefore unbalanced with regard to the proton and electron number.
Metals tend to give up or donate electrons and non-metals like to take up or acquire electrons. The charge of an any ion will be either + (plus) or – (minus). Here are typical charges found on common metals: Na+, K+, Ca++, Mg++, Mn++, Cu+ or Cu++.

What are compounds and how are they formed?

Compounds are the union of two or more atoms of elements held to one another by a chemical bond. Thus, CO, CO2, CH4, NaCl and H2O are clear examples of chemical compounds.

What is a molecule?

A molecule is one complete and small unit of any compound that still has the properties of that compound. A molecule of table salt is written as NaCl and one NaCl molecule is a single and complete unit of that compound.

Examples of elements and their names and symbols are:

Some common elements and their designated symbols are: carbon (C), hydrogen (H), oxygen (O), nitrogen (N), phosphorous (P), sulfur (S), sodium (Na), potassium (K), chlorine (Cl). The group of elements CHONPS are called the macroelements of life and living things. These six elements are critical for the structure and function of living things and constitute  the major elements of the body.

Elements –Atomic Properties and Characteristics – Atomic Number & Mass

Each element has distinct and special properties. Therefore, no two elements are exactly the same and each has special, unique and distinct features.

The properties of an element are determined by the  atomic structure of each element. The atomic structure is the result careful and detailed study of each element in its pure state. When this analysis is done each element is found to have a distinctive atomic number and a distinctive atomic weight. Listed following are important examples of these physical features:

carbon (C6). Carbon chemistry is part of organic chemistry. Simple carbon compounds include carbon monoxide (CO), carbon dioxide (CO2), methane gas (CH4) and simple sugar (C6H12O6). Carbon has 6 protons and 6 neutrons and 6 electrons. The atomic weight of carbon is 12.

 hydrogen (H1). Hydrogen is the lightest known element. It has only one proton, one electron and no neutrons (exception: isotopes of hydrogen, deuterium and tritium have, respectively, 1 and 2 neutrons). Therefore, the atomic weight of ordinary hydrogen is 1. Hydrogen gas is composed of two bonded hydrogen atoms (H2) and because there are two atoms of hydrogen, it has a molecular weight of 2. Hydrogen is important for pH which is a  measure of the concentration or amount of hydrogen ions (H+) in a solution. Hydrogen is found in many thousands of different compounds including the two mentioned above: methane gas (CH4) and simple sugar (C6H12O6).

oxygen (O8) . Is the element essential for most life and living organisms. It has 8 protons, 8 neutrons and 8 electrons. The atomic weight of oxygen is 16. Oxygen is found in many different compounds some of which are noted above and you should find them and review their names. Oxygen as a gas in the air is written as O2. Because there are two atoms of oxygen, it has a molecular weight of 32.

 nitrogen (N7), Notice that nitrogen has only 1 less proton than oxygen. Check and compare the atomic numbers of oxygen and nitrogen and the atomic weights of each right now. Nitrogen is a totally different element with different properties from those of oxygen. So, this confirms to all of us that proton numbers determine each element and influences its overall characteristics and properties.

One nitrogen can be bound to another nitrogen and nitrogen is found in the air as a gas N2.  Nitrogen gas constitutes 78% of common air we breathe every day. Oxygen gas constitutes 21% of the air we breathe every day. Therefore, 99% of the air we breathe is composed of molecules of nitrogen and oxygen gasses.

What is the molecular weight of nitrogen gas? Hint: add the atomic weights of both nitrogens to get the molecular weight.

 phosphorous (P15). Phosphorous is found in nature as inorganic phosphates (PO4) and is very common in soil and rocks. Phosphates are also very important in the biochemical of life: cell membranes, DNA, RNA and ATP.

Phosphorous has an atomic weight of 31. How many neutrons does phosphorous have if you know the number of protons based on the atomic number?  

sulfur (S16). Sulfur is found in nature as sulphates (SO4) and sulphites (SO3) and the foul-smelling H2S (hydrogen sulfide gas that smells like rotten eggs). Sulfur is found in two amino acids and is important in cell protein structures including enzymes, hair, skin and nails. If hair is burned or singed it smells like sulfur due to SO2 (sulfur dioxide) formed when sulfur-containing amino acids are burned and oxidized by oxygen in the air.

sodium (Na11), Sodium and potassium are two important light metallic elements that when ionized, loses one electron and become positively charged and exists as Na+. Sodium as a normal atom has 11 protons, 11 electrons and 12 neutrons. Based on this information what is the atomic weight of sodium?

Sodium is important in ionic and electron balance in the cell. Sodium, like potassium, is involved in nerve signals and charge.  

potassium (K19). Potassium has 19 protons and the same number of electrons (remember all atoms are balanced electrically). Potassium can lose one electron and assume a charge as an ion of K+. If there are 20 neutrons in potassium what is its atomic weight?

chlorine (Cl17). Chlorine is an example of a non-metallic element.

If there is an electron nearby, each chlorine atom can add one electron to its outer shell. Whenever a chlorine atom adds an electron, it becomes minus 1.

In summary, each chlorine element forms a chloride ions (Cl-) whenever it has an electron added to its outer shell of electrons.
What is a chemical mixture?
A chemical mixture is composed of elements or compounds that are not reactive. Water mixed with oil is a mixture. When salt is mixed with sugar or pepper none of these react. They are simply in a mix or mixture together.
What is a chemical reaction?
A chemical reaction is a change in the actual composition of the atoms innvolved in the chemical reaction.
Mix H2 gas with some air and ignite the gas by spark or flame and you get an explosion with light, he and water as endproducts.
H2 + O2 -----> H2O, light, heat
Mix a strong acid like hydrochloric acid with a strong base like sodium hydroxide and you get salt and water. That is another real and strong kind of chemical reaction.
HCl + NaOH -----> NaCl and HOH (H2O)
Guess this chemical reaction.
Fe (iron) + O2 (oxygen in air)---->
Fe2O3
What is in that final reaction product?
Clue: People who don't use their minds or hone their skills often get rusty.
I know: bad joke and ending, but it is a real clue if you read it in the right way.
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