Tag Archives: electron

Element Valency PDF

Fluroine Atom

The outer shell of a fluorine atom contains 7 electrons. This means it has one less electron than needed to complete the shell. This gives fluorine a -1 valence.

This element Valency PDF is a downloadable version of the Valences of the Elements table.

Download PDF Download PDF

As in the table, the most common valences are in BOLD text where values in italics are theoretical values based on periodic table trends.

This table requires three sheets of paper to print. If you prefer a more compact version, this information is available in periodic table form. There is a Color Periodic Table of the Elements or a Black and White version. A simpler version listing only the most common valence charges is also available.

This is page 1 of the PDF file. It contains the valences of the first 45 elements.

Element Valences 1-45Elements 46-118 can be found in the PDF.

 

Periodic Table Showing Shells

This periodic table contains each element’s atomic number, symbol, name, atomic weight and electron configuration.

Periodic Table Electron Configuration with Orbital BlocksIt is a periodic table showing shells of the outermost electron orbital. Each lightly colored cell highlights the block of the outermost electron. Block s elements are green, p is blue, d is pink and f block elements are purple. This table is useful to illustrate why the periodic table is shaped the way it is.

This table is 1920×1080 pixels in dimension and suitable as a HD wallpaper for widescreen devices. Click the image to view full-size.

If you would like to print this table, download the PDF and select Fit and Landscape as your print options. The results are quite readable on an 8½ x 11 sheet of paper.

Download and enjoy! Be sure to check out our other periodic table wallpapers.

How To Calculate Atomic Mass Tutorial

Helium Atom

Helium atom. This helium atom has two protons, two neutrons and two electrons. The atomic mass of this atom would be 4 amu. Credit: Todd Helmenstine

Atomic mass is the mass of a single atom. This is found by adding up all the protons, neutrons and electrons in the atom. One proton has a mass of 1,836 electrons. Since electrons barely change the outcome of the atomic mass, they are generally left out of the calculation. This tutorial will show how to calculate the atomic mass using three different methods, depending on your situation.

1. Look it up.

Sounds easy, but why do work that’s already been done? Instructors will ask for atomic masses when teaching how to use a periodic table. Atomic masses are often listed on the periodic table as a decimal value, usually under the element symbol or name. These numbers need a unit of mass associated with them. Atomic masses are usually given in atomic mass units, or amu, where

1 amu = 1/12 the mass of one Carbon-12 atom.

A common unit of amu is the Dalton. One Dalton = 1 amu. These two units can be used interchangeably. The amu unit is not often used in chemistry. Instead the atomic mass is equal to the number grams of the element in one mole of atoms of the element. The units of measurement for this is grams/mole, or simply g/mol.

Example: Find the atomic mass of nitrogen.

Nitrogen is element number 7. Using this periodic table, we see the atomic mass of nitrogen is 14.01 amu or 14.01 g/mol.

2. Add up the number of neutrons and protons in a single atom.

If the mass of a single atom is needed, simply count the number of protons and neutrons in the atom.

Example: What is the atomic mass of a carbon isotope with 8 neutrons?

Carbon is element 6. The element number of an element is the number of protons in the atom’s nucleus. Carbon has 6 protons.
6 protons + 8 neutrons = 14

The atomic mass of this carbon isotope is 14 amu.

3. Calculate a weighted average of all the atoms of an element.

Atomic masses are calculated from weighted averages of all that element’s isotopes based on their abundance. Typically, homework problems will provide you with a sample of an element with a list of all isotopes, their mass and their percent abundance. To solve these problems, follow these two steps:

1. Multiply each isotope’s mass by the percent abundance and divide by each value by 100.
2. Add all these values together.

Example: You are given a sample of carbon that contains 75% carbon-12 and 25% carbon-14. What is the average atomic mass of this sample?
Let’s start with carbon-12. Carbon-12 has an atomic mass of 12. 75% of the sample was carbon-12, so multiply the atomic mass by 75
12 x 75 = 900.
Divide this answer by 100
900/100 = 9

Carbon-14 has an atomic mass of 14. 25% of the sample was this isotope. Multiply the atomic mass of the isotope by 25.
14 x 25 = 350
Divide this by 100
350/100 = 3.5

Add these two values together
9 + 3.5 = 12.5

The average atomic mass of this sample was 12.5 amu.

This should help you with any atomic mass homework problems you may encounter. If you’d like some other example problems, one can be found here and here.

Table of Valences of the Elements

A lithium atom has one outer shell electron, so it's usual valence is +1, but it can lose the electron and have a valence of -1.

A lithium atom has one outer shell electron, so it’s usual valence is +1, but it can lose the electron and have a valence of -1.

This is a table of the valences or oxidation states of the elements. The most common valences are in BOLD. Values in italics are predicted theoretical values.

This information is available on a Color Periodic Table of the Elements or a Black and White version. A simpler version listing only the most common valence charges is also available.

 NUMBER SYMBOLELEMENTVALENCE
1HHydrogen1, 0, -1
2HeHelium0
3LiLithium1, -1
4BeBeryllium2
5BBoron3, 2, 1
6CCarbon4, 3, 2, 1, -1, -2, -4
7NNitrogen5, 4, 3, 2, 1, 0, -1, -2, -3
8OOxygen2, 1, 0, -1, -2
9FFluorine0, -1
10NeNeon0
11NaSodium1, -1
12MgMagnesium2
13AlAluminum3, 1
14SiSilicon4, 3, 2, 1, -1, -2, -4
15PPhosphorus5, 4, 3, 2, 1, 0, -1, -2, -3
16SSulfur6, 5, 4, 3, 2, 1, 0, -1, -2
17ClChlorine6, 5, 4, 3, 2, 1, 0, -1, -2
18ArArgon0
19KPotassium1, -1
20CaCalcium2
21ScScandium3, 2, 1
22TiTitanium4, 3, 2, 0, -1, -2
23VVanadium5, 4, 3, 2, 1, 0, -1, -2
24CrChromium6, 5, 4, 3, 2, 1, 0, -1, -2, -3, -4
25MnManganese7, 6, 5, 4, 3, 2, 1, 0, -1, -2, -3
26FeIron6, 5, 4, 3, 2, 1, 0, -1, -2
27CoCobalt5, 4, 3, 2, 1, 0, -1
28NiNickel6, 4, 3, 2, 1, 0, -1
29CuCopper4, 3, 2, 1, 0
30ZnZinc2, 1, 0
31GaGallium3, 2, 1
32GeGermanium4, 3, 2, 1
33AsArsenic5, 3, 2, -3
34SeSelenium6, 4, 2, 1, -2
35BrBromine7, 5, 4, 3, 1, 0, -1
36KrKrypton2, 0
37RbRubidium1, -1
38SrStrontium2
39YYttrium3, 2
40ZrZirconium4, 3, 2, 1, 0, -2
41NbNiobium5, 4, 3, 2, 1, 0, -1, -3
42MoMolybdenum6, 5, 4, 3, 2, 1, 0, -1, -2
43TcTechnetium7, 6, 5, 4, 3, 2, 1, 0, -1, -3
44RuRuthenium8, 7, 6, 5, 4, 3, 2, 1, 0, -2
45RhRhodium6, 5, 4, 3, 2, 1, 0, -1
46PdPalladium4, 2, 0
47AgSilver3, 2, 1, 0
48CdCadmium2, 1
49InIndium3, 2, 1
50SnTin4, 2, -4
51SbAntimony5, 3, -3
52TeTellurium6, 5, 4, 2, 1, -2
53IIodine7, 5, 3, 1, 0, -1
54XeXenon8, 6, 4, 3, 2, 0
55CsCesium1, -1
56BaBarium2
57LaLanthanum3, 2
58CeCerium4, 3, 2
59PrPraseodymium4, 3, 2
60NdNeodymium4, 3, 2
61PmPromethium3
62SmSamarium3, 2
63EuEuropium3, 2
64GdGadolinium3, 2, 1
65TbTerbium4, 3, 1
66DyDysprosium4, 3, 2
67HoHolmium3, 2
68ErErbium3
69TmThulium3, 2
70YbYtterbium3, 2
71LuLutetium3
72HfHafnium4, 3, 2, 1
73TaTantalum5, 4, 3, 2, 1, -1, -3
74WTungsten6, 5, 4, 3, 2, 1, 0, -1, -2, -4
75ReRhenium7, 6, 5, 4, 3, 2, 1, 0, -1, -3
76OsOsmium8, 7, 6, 5, 4, 3, 2, 1, 0, -2
77IrIridium6, 5, 4, 3, 2, 1, 0, -1
78PtPlatinum6, 5, 4, 2, 0
79AuGold7, 5, 3, 2, 1, 0, -1
80HgMercury2, 1
81TlThallium3, 1
82PbLead4, 2
83BiBismuth5, 3, 1, -3
84PoPolonium6, 4, 2, -2
85AtAstatine7, 5, 3, 1, -1
86RnRadon2, 0
87FrFrancium1
88RaRadium2
89AcActinium3
90ThThorium4, 3, 2
91PaProtactinium5, 4, 3
92UUranium6, 5, 4, 3, 2
93NpNeptunium7, 6, 5, 4, 3, 2
94PuPlutonium7, 6, 5, 4, 3, 2
95AmAmericium7, 6, 5, 4, 3, 2
96CmCurium6, 5, 4, 3, 2
97BkBerkelium4, 3, 2
98CfCalifornium5, 4, 3, 2
99EsEinsteinium4, 3, 2
100FmFermium4, 3, 2
101MdMendelevium3, 2, 1
102NoNobelium3, 2
103LrLawrencium3, 2
104RfRutherfordium4, 3
105DbDubnium5, 4
106SgSeaborgium6, 5, 4
107BhBohrium7, 6, 5, 4, 3
108HsHassium8, 7, 4, 3, 2
109MtMeitnerium6, 5, 4, 3, 2, 1
110DsDarmstadtium6, 5, 4, 3, 2, 1
111RgRoentgenium3, -1
112CnCopernicium2, 1
113UutUnuntrium1
114FlFlerovium2
115UupUnunpentium3, 1
116LvLivermorium4, 2
117UusUnunseptiumunknown
118UuoUnunoctium8, 6, 4, 2