The Periodic Table is a tabular arrangement of the elements in increasing order oftheir atomic numbers, so that elements with similar properties are in the same column. There are 18 columns, called groups, and seven rows, which are called periods, in the modern periodic table. Questions about the Periodic Table: its history and creation, trends, groups/families, and periods are asked in our Periodic Table category.
Asked in Science, Chemistry, Periodic Table
What is the fourth element of the periodic table of elements?
Asked in Periodic Table, Energy, Elements and Compounds
What are the first 20 elements of the periodic table?
What type of element is a protactinium?
I'm not too bad at chemistry, but one thing I can't wrap my head around is how perfect the periodic table is. How is it that each element that we know is only one more proton than the last? How come it goes in PERFECT order instead of having a few elements with protons not perfectly linear to the periodic table?
Asked in Science, Periodic Table
What are some materials or things that change from solid to gas?
Asked in Health, Biology, Periodic Table, Scientific Method
What is Clinistix and albustix used for?
Which is the hardest metal among the group IA in periodic table?
Asked in Chemistry, History of Science, Periodic Table
Who created the periodic table?
The first periodic table was developed by Dmitri Mendeleev in the mid-19th century.He wasn't the only person thinking along those lines ... both John Newlands and Lothar Meyer had proposed similar ideas However, Newlands was largely criticized and ignored at the time, and Meyer didn't make any predictions, so Mendeleev's table (which did make predictions about the properties of several as-yet-undiscovered elements) is generally regarded as the first.
What is the mass number of an atom?
A mass number is the total number of protons and neutrons found in an atom. To find the mass number, you must know the number of neutrons in that particular isotope of the element and then add the atomic number (same as the number of protons) to it. When this number is definite it is called a nuclide and the symbol is written with a superscript giving the mass number and a subscript giving the atomic number (number of protons) placed in front of atomic symbol: 2311Na. It can also be written after the elements name, sodium-23. Do not confuse this with the atomic number, which is the number of protons. .
Asked in Chemistry, Periodic Table
How did Henry Moseley organize his periodic table?
Henry Moseley did a series of experiments looking at the x-ray spectra of various elements. He found that the frequencies of equivalent bands made a very simple progression that more or less corresponded to atomic weight order. The exceptions were exactly the same as the ones where Mendeleev's scheme was having difficulties. He thus arrived at a definition of atomic number, and proposed a revised periodic law where the ordering of elements was according to atomic number rather than atomic weight.
Why do people use non-aqueous solvents?
Different reactions require different solvents. Sometimes the polarity of H2O can hinder the progression of the reaction by H-bonding to the reactants. Also, sometimes a reaction requires a stronger or weaker solvent to insure that you have your reactants reacting and not a reactant with the solvent.
Asked in Chemistry, Periodic Table
Colored salts generallly have a cation from which section of the periodic table?
Coloured salts generally have a cation which is a transition metal. Iron, Chromium, Manganese, Vanadium and Copper all are examples of transition metals that make colourful salts. Notice that there are exceptions - particularly the period 6 main group metals like lead share some of the properties of the transition group metals and can make colourful salts - the bright yellow precipitate of lead iodide (PbI) is an example commonly used as demonstration of precipitation reactions.