Inorganic Chemistry/Introduction to Elements

Introduction to Elements thumb|750px|Periodic Table of ElementsAn Element is one of a limited class of substances composed entirely of atoms that have an invariant nuclear charge and which cannot be further divided by ordinary chemical methods. Atoms having the same nuclear charge have the same number of protons in the nucleus. This number is called atomic number, denoted as Z, derived from the first letter of name of the greatest Ancient Greek god Zeus. As of May 2011, 118 elements have been found. An Isotope is a set of atoms that have the same number of protons and neutrons in the nucleus. For example, Element Hydrogen (denoted as H) is a set of atoms that have one proton in their nuclei. This set has 3 subsets (Isotopes): Protium or Hydrogen-1 (the first name is rarely used), Deuterium and Tritium. A protium is an atom that has one proton in its nucleus and no neutrons, while a deuterium not only has one proton but also 1 neutrons. In case of tritium, the number of neutrons is double: 2 neutrons in the nucleus. In the context of this book, I use lower case for the reference to an object of a set, and use upper case for that set. For example, I use 'Deuterium' when I want to refer to a set of atoms that have one proton and one neutron in the nucleus, and use 'deuterium' when I want to refer to a single atom of the set. I use 'Isotope' for the reference to an Isotope, and 'isotope' to refer to an atom of that Isotope. The same thing for 'Element' and 'element'. Although the name of an element is considered as uncountable, in the scope of this book I use that name as a short-handed version for 'an atom of an Element'. For example 'an atom of Hydrogen' can be written as 'a hydrogen' in this book. Another note is: every time you want to refer to element and you don't care about the different in the number of neutrons they have, use the Element's name in lower case. If you want to refer to an atom of a specific set of an element, use the Isotope's name in lower case. For example: 1) Water consists of hydrogen and oxygen (I don't care about the isotopes of Hydrogen and Oxygen) 2) A tritium has 1 proton and 2 neutrons in its nucleus (now I care!) Rule: upper case for set, lower case for object Element Denotation The following assumes you have already known the mass and charge of a proton, neutron and electron. If you don't know or you have forgotten, review lesson 1, First Glance At Subatomic Particles Every Element has a symbol, usually the first letter of its name in English, but sometimes derived from the element's name in Latin or some other language. Hydrogen is H, Oxygen is O, Nitrogen is N etc. This symbol also represents an element (an atom of an Element). A atom of Hydrogen is H, of Oxygen is O and of Nitrogen is N etc. This convention (using the same letter for an Element and an element) is particularly popular in chemical equations. As many other convention in science is not always convenient with all people, this one is not convenient with me since it violates my rule. Nevertheless, you can use any symbols you like as long as you understand the concept. Remember you are learning how the nature works, not how the scientists denote things :) I use lower case all together when writing chemical equations to avoid confusion. But when I publish it, I use LibreOffice to switch them back to upper case :) Okay, let's go back to our study. Instead of writing 'Protium', 'Deuterium' or 'Tritium', you can write 1H, 2H and 3H respectively. The '1', '2', '3' above the H to the left is the mass number, denoted as A, which is the total number of protons and neutrons in the nucleus. Sometimes it can be called more appropriately as nucleon number. I prefer the second name, so I will use it throughout this book. This denotation is particularly useful to refer to an Isotope of an Element Sometimes you can see the atomic number (the number of protons in the nucleus) written below the nucleon number, as in , , . However, it is not necessary, because the 'H' has already told us that this is a set of atoms having one proton in the nucleus. Again, the note comes in. When you see 1H elsewhere apart from this book, it can mean a set of atoms or an atom. List of Elements If we define atomic number as the number of protons an atom has in its nucleus, then atomic number should be applied to a specific atom, not a set of atoms. Therefore, the first column is named 'Atomic number of element'. + List of elementsAtomic number of element ElementSymbolGroupPeriodBlockState at Standard temperature and pressure (STP) Occurrence Description 1 Hydrogen H 1 1 s Gas Primordial Non-metal 2 Helium He 18 1 s Gas Primordial Noble gas 3 Lithium Li 1 2 s Solid Primordial Alkali metal 4 Beryllium Be 2 2 s Solid Primordial Alkaline earth metal 5 Boron B 13 2 p Solid Primordial Metalloid 6 Carbon C 14 2 p Solid Primordial Non-metal 7 Nitrogen N 15 2 p Gas Primordial Non-metal 8 Oxygen O 16 2 p Gas Primordial Non-metal 9 Fluorine F 17 2 p Gas Primordial Halogen 10 Neon Ne 18 2 p Gas Primordial Noble gas 11 Sodium Na 1 3 s Solid Primordial Alkali metal 12 Magnesium Mg 2 3 s Solid Primordial Alkaline earth metal 13 Aluminium Al 13 3 p Solid Primordial Metal 14 Silicon Si 14 3 p Solid Primordial Metalloid 15 Phosphorus P 15 3 p Solid Primordial Non-metal 16 Sulfur S 16 3 p Solid Primordial Non-metal 17 Chlorine Cl 17 3 p Gas Primordial Halogen 18 Argon Ar 18 3 p Gas Primordial Noble gas 19 Potassium K 1 4 s Solid Primordial Alkali metal 20 Calcium Ca 2 4 s Solid Primordial Alkaline earth metal 21 Scandium Sc 3 4 d Solid Primordial Transition metal 22 Titanium Ti 4 4 d Solid Primordial Transition metal 23 Vanadium V 5 4 d Solid Primordial Transition metal 24 Chromium Cr 6 4 d Solid Primordial Transition metal 25 Manganese Mn 7 4 d Solid Primordial Transition metal 26 Iron Fe 8 4 d Solid Primordial Transition metal 27 Cobalt Co 9 4 d Solid Primordial Transition metal 28 Nickel Ni 10 4 d Solid Primordial Transition metal 29 Copper Cu 11 4 d Solid Primordial Transition metal 30 Zinc Zn 12 4 d Solid Primordial Transition metal 31 Gallium Ga 13 4 p Solid Primordial Metal 32 Germanium Ge 14 4 p Solid Primordial Metalloid 33 Arsenic As 15 4 p Solid Primordial Metalloid 34 Selenium Se 16 4 p Solid Primordial Non-metal 35 Bromine Br 17 4 p Liquid Primordial Halogen 36 Krypton Kr 18 4 p Gas Primordial Noble gas 37 Rubidium Rb 1 5 s Solid Primordial Alkali metal 38 Strontium Sr 2 5 s Solid Primordial Alkaline earth metal 39 Yttrium Y 3 5 d Solid Primordial Transition metal 40 Zirconium Zr 4 5 d Solid Primordial Transition metal 41 Niobium Nb 5 5 d Solid Primordial Transition metal 42 Molybdenum Mo 6 5 d Solid Primordial Transition metal 43 Technetium Tc 7 5 d Solid Transient Transition metal 44 Ruthenium Ru 8 5 d Solid Primordial Transition metal 45 Rhodium Rh 9 5 d Solid Primordial Transition metal 46 Palladium Pd 10 5 d Solid Primordial Transition metal 47 Silver Ag 11 5 d Solid Primordial Transition metal 48 Cadmium Cd 12 5 d Solid Primordial Transition metal 49 Indium In 13 5 p Solid Primordial Metal 50 Tin Sn 14 5 p Solid Primordial Metal 51 Antimony Sb 15 5 p Solid Primordial Metalloid 52 Tellurium Te 16 5 p Solid Primordial Metalloid 53 Iodine I 17 5 p Solid Primordial Halogen 54 Xenon Xe 18 5 p Gas Primordial Noble gas 55 Caesium Cs 1 6 s Solid Primordial Alkali metal 56 Barium Ba 2 6 s Solid Primordial Alkaline earth metal 57 Lanthanum La 3 6 f Solid Primordial Lanthanide 58 Cerium Ce 3 6 f Solid Primordial Lanthanide 59 Praseodymium Pr 3 6 f Solid Primordial Lanthanide 60 Neodymium Nd 3 6 f Solid Primordial Lanthanide 61 Promethium Pm 3 6 f Solid Transient Lanthanide 62 Samarium Sm 3 6 f Solid Primordial Lanthanide 63 Europium Eu 3 6 f Solid Primordial Lanthanide 64 Gadolinium Gd 3 6 f Solid Primordial Lanthanide 65 Terbium Tb 3 6 f Solid Primordial Lanthanide 66 Dysprosium Dy 3 6 f Solid Primordial Lanthanide 67 Holmium Ho 3 6 f Solid Primordial Lanthanide 68 Erbium Er 3 6 f Solid Primordial Lanthanide 69 Thulium Tm 3 6 f Solid Primordial Lanthanide 70 Ytterbium Yb 3 6 f Solid Primordial Lanthanide 71 Lutetium Lu 3 6 d Solid Primordial Lanthanide 72 Hafnium Hf 4 6 d Solid Primordial Transition metal 73 Tantalum Ta 5 6 d Solid Primordial Transition metal 74 Tungsten W 6 6 d Solid Primordial Transition metal 75 Rhenium Re 7 6 d Solid Primordial Transition metal 76 Osmium Os 8 6 d Solid Primordial Transition metal 77 Iridium Ir 9 6 d Solid Primordial Transition metal 78 Platinum Pt 10 6 d Solid Primordial Transition metal 79 Gold Au 11 6 d Solid Primordial Transition metal 80Mercury Hg 12 6 d Liquid Primordial Transition metal 81 Thallium Tl 13 6 p Solid Primordial Metal 82 Lead Pb 14 6 p Solid Primordial Metal 83 Bismuth Bi 15 6 p Solid Primordial Metal 84 Polonium Po 16 6 p Solid Transient Metalloid 85 Astatine At 17 6 p Solid Transient Halogen 86 Radon Rn 18 6 p Gas Transient Noble gas 87 Francium Fr 1 7 s Solid Transient Alkali metal 88 Radium Ra 2 7 s Solid Transient Alkaline earth metal 89 Actinium Ac 3 7 f Solid Transient Actinide 90 Thorium Th 3 7 f Solid Primordial Actinide 91 Protactinium Pa 3 7 f Solid Transient Actinide 92 Uranium U 3 7 f Solid Primordial Actinide 93 Neptunium Np 3 7 f Solid Transient Actinide 94 Plutonium Pu 3 7 f Solid Primordial Actinide 95 Americium Am 3 7 f Solid Synthetic Actinide 96 Curium Cm 3 7 f Solid Synthetic Actinide 97 Berkelium Bk 3 7 f Solid Synthetic Actinide 98 Californium Cf 3 7 f Solid Synthetic Actinide 99 Einsteinium Es 3 7 f Solid Synthetic Actinide 100 Fermium Fm 3 7 f Solid Synthetic Actinide 101 Mendelevium Md 3 7 f Solid Synthetic Actinide 102 Nobelium No 3 7 f Solid Synthetic Actinide 103 Lawrencium Lr 3 7 d Solid Synthetic Actinide 104 Rutherfordium Rf 4 7 d Synthetic Transition metal 105 Dubnium Db 5 7 d Synthetic Transition metal 106 Seaborgium Sg 6 7 d Synthetic Transition metal 107 Bohrium Bh 7 7 d Synthetic Transition metal 108 Hassium Hs 8 7 d Synthetic Transition metal 109 Meitnerium Mt 9 7 d Synthetic 110 Darmstadtium Ds 10 7 d Synthetic 111 Roentgenium Rg 11 7 d Synthetic 112 Copernicium Cn 12 7 d Synthetic Transition metal 113 (Ununtrium) Uut 13 7 p Synthetic 114 (Ununquadium) Uuq 14 7 p Synthetic 115 (Ununpentium) Uup 15 7 p Synthetic 116 (Ununhexium) Uuh 16 7 p Synthetic 117 (Ununseptium) Uus 17 7 p Synthetic 118 (Ununoctium) Uuo 18 7 p Synthetic Exercises The following exercises help you utilize the concepts you have learned. Work through them yourself, try to think a way to tackle the problem. How many protons are there in the following atoms: h, fe, cu, al, n, o, c. How many neutrons are there in the following atoms: , , , , , , . Draw an illustration for each of the following atoms: , , , , , , , . Assume electrons are on a same circle. Draw each proton, neutron and electron as a ball. Specify the name of each of the following atoms. Because of the large atomic number. I draw all protons (and neutrons) as a big ball. Hints Look up the List of Elements to find the atomic number, which is the number of protons an element has. You see the nucleon number as a left superscript. Look up the List of Elements to find the atomic number. Since the nucleon number is the sum of particles in the nucleus, when you subtract it by the atomic number, you get the number of neutrons the atom has. First you need to look up the atomic number of an element. It is the number of protons the atom has. Subtract it from the nucleon number then you have the number of neutrons. Neutrons and protons make the nucleus of the atom. In normal stage, the number of protons equals the number of electrons in an atom. Draw electrons moving around the nucleus. Solutions **1** element number of protons h 1 fe 26 cu 29 al 13 n 7 o 8 c 6 **2** element number of neutrons 2 16 74 12 20 10 12 **3** element illustation thumb|600px thumb|600px thumb|600px thumb|600px thumb|600px thumb|600px thumb|600px thumb|600px **4** Illustration element thumb|600px thumb|600px thumb|600px thumb|600px thumb|600px thumb|600px thumb|600px Thinking This session helps you build your critical thinking. Try to answer yourself, write it down a paper. The answers provided here are only a reference, there may be other answers as well. If you have another answer, feel free to add :) You know the atomic number is denoted as a Z. You also know why scientists choose that letter. But why is the nucleon number denoted as an A? Why are protons, neutrons denoted as p and n respectively? Why are electrons denoted as e-? Can protons and neutrons be denoted as p+ and n+ respectively? In the scope of this book, what does an element and an isotope mean? What details are they different from? Answers to Thinking In convention, the atomic number is written as a subscript to the left of the Element's name, such as in . The nucleon number is written above it, such as in . Nucleon number is the above, atomic number is the below, just the same as 'A' is the first letter, 'Z' is the last. They are denoted after their first letter. Electrons can be denoted as the letter e, just the same as the case of protons and neutrons. But later the scientists found their anti-particles, called positrons. Positrons have almost the same characteristics as electrons, except for the charge. The charge of a positron over the elementary charge is +1, while in case of an electron, -1. Positrons were later named e+, electrons e- Yes, I think protons can be denoted as p+ while their anti-particles, p-. But the neutrons would not. They have no charge, so '+' or '-' doesn't have any meaning. If they were ever denoted like that, there would be other reasons. An element is an atom of an Element. An isotope is an atom of an Isotope. When we say a hydrogen, we refer to an atom that may be a protium, deuterium or tritium. When we say a tritium, we only refer to an atom of Tritium.