is there a easy way 2 remember the atomic number & atomic mass of the elements in chemistry?
921867
As you work with th periodic table you will remember the important ones. You always have a periodic table to work with. In quantiitative analysis you need to use all those decimal places in your calculations.
608949
cant answer secifically, but you should be able to back calculte taking elements present today and using the half lives as your main variable.
123587
Periodic Table is in order of increasing atomic no. so\n\n1st Step: find the placement of the element, in the present case it is on third place so no. of protons is three.\n\n2nd Step: In the Periodic Table, number of electron is always equal to number of protons so far three protons of Lithium there will be three electrons.\n\n3rd Step: Periodic Table also give atomic weights of the elements. Simply atomic weight is equal to sum of number of protons and nutroms.\n\n4th Step: Note the atomic weight of the element. Most of the elements in Periodic Table show atomic weights in fractions. In the case of Lithium it is 6.9 \n\n5th Step: Convert the fractional figure into nearest whole number. In case of Lithium it is 7\nNote:In the Periodic Table atomic weight is average of all isotopes (different atomic weights of same element). The nearest whole number refers to the most abundent  or the common atom (Isotop).\n\n6th Step: Subtract atomic number (protons) from atomic weight (neutron=proton), the difference is number of neutrons. In Lithium 7-3=4 so there are 4 neutrons
1101474
hey try this:\n\n1. if u can't remember equations practise them by writing them again and again\n\n2.u can write all name reactions on a sheet of paper and paste it them on ur almirah,so everytime u open it to get ready for school,revise it.Also get two photostated copy of this paper. and revise them by getting up in the morning,while going to school etc,.\n\n3.note down all the formulaes in the book on  a single sheet of paper,it becomes easier to remember them this way and do one or two numericals on each of these formula.\n\n4.Learn definitions,derivations completely,because it is where u can  get full marks .\n\n5. besides study hard.\n\nand alwys remember this:u cannot achieve success in ur life if u don't get motivated.\n\n\nbest of luck
213411
Atomic Number 3\nhttp://www.jergym.hiedu.cz/~canovm/vyhledav/varianty/litva.gif
254930
Chemfinder.com  \nYou have to register with the site to use it but it's completely free, and about as easy as them come. You can just copy and paste the structure you need.
954638
It seems that you have problems with moles and Avagadro's number. You will need to refer to your periodic table to get the molecular weights that your teacher wants you to use.\n\nSo get the molecular weights of the elements you are working with from your periodic table and substitute in the formula.\n\nI am using round numbers to show the substitution you should know how many decimal points you need to work to.\n\nHG atomic weight 200\nO atmic weight 16\n\nSubstitute in the formula to get the masses involved\n\n2 HgO(s) - 2 Hg(l) + O2(g) Hrxn = 181.6 kJ\n 2 (200g + 16g)   =  2(200g) + 2(16g) = 181.6 kj  \n\n432g oxide decomposes releasing 181.6Kj\n\nQuestion a)\nStraightforward ratio. X = the no of KJ required\n\n572g/432g = xkj/181.6kj\n\nYou'll need to calculate the molecular mass from you periodic table substitute it for the 432 and then refine the equation.\n\nQuestion b) Straightforward ratio. X = the no of KJ required\n\nYou'll need to calculate the molecular mass from you periodic table substitute it for the 432 and then refine the equation.\n\n289/181.6 = xg/432\n\nA mole is the amount of pure substance containing the same number of chemical units as there are atoms in exactly 12 grams of carbon-12 (i.e., 6.023 X 1023). This involves the acceptance of two dictates -- the scale of atomic masses and the magnitude of the gram. Both have been established by international agreement. Formerly, the connotation of "mole" was "gram molecular weight." Current usage tends to apply the term "mole" to an amount containing Avogadro's number of whatever units are being considered. Thus, it is possible to have a mole of atoms, ions, radicals, electrons, or quanta. This usage makes unnecessary such terms as "gram-atom," "gram-formula weight," etc.
29071
Well, look in the periodic table of the elements and find the molecular weight. The molecular weight tells you how many grams are in one mole of that element. Once you know the amount of grams that correspond to 1 mole, you do the math.\nGood luck!
764097
Find the atomic number of elements.\n\nFind other data about the elements (molar mass, electronegativity, etc).\n\nPredict the properties of elements based on know properties of other elements in the same column or row.\n\nPredict the properties that have not been discovered yet.
697898
pull out your periodic table and this becomes very easy.  elements have an oxidation # of 0.
16762
The atomic number is the number of protons.
714340
look up the periodic table...duh
1045065
ya , using the avogadro's number that is \n6.022 * 10 ^ 23\nits formula is \nno. of atoms if we have to find out\nthe no of atoms = given mass of the element /gram atomic mass * 6.022* 10 ^ 23
842499
First of all, look on your periodic table.  Somewhere there should be a listing for atomic mass.  Usually it's either at the very bottom of the square for that element or in a separate table.  That is how much that atom weighs in amu, or atomic mass units.  A molecule weighs as much as all the atoms in it put together.\n\nA guy named Avogadro came up with a number called Avogadro's number (modest character, wasn't he?) or a mole.  A mole is 6.023 * 10^23.  There are exactly one mole of amus in a gram.  Atoms are commonly measured in moles in the lab as well, since the actual number of atoms is usually way too high to work with conveniently.\n\nSo to answer your question, the number of atoms in a sample is (6.023 * 10^23 * the number of grams)/the atomic mass.  The number of molecules is (6.023 * 10^23 * the number of grams)/the sum of the atomic masses of the component atoms (also called the molecular mass).  But most of the time, amounts are reported in moles, and the number of moles is simply the number of grams/the atomic or molecular mass.\n\nI hope that made sense to you.
92358
Just count the (sigma) bonds and the lone electron pairs and memorize the cooresponding geometric shapes.  Sorry, but it's the only way.
906161
Measure the mass of a nickle, then use the atomic weights of each element to determine the number of nickel atoms.  I won't do you're homework for you, but that should get you started.
974811
This is an answer I gave a few weeks ago. It helped me to get from failing Chemistry to University....maybe it will help you to understand the periodic table as well.\n\nMy Chemistry teacher taught me a great story which helped me learn the elements, which groups they were in, which periods, how many electrons they had etc and resulted in me going from a grade F to B. Every kid should learn this.\n\nHorrible Hairy Little Begger Boys Catch Newts On Friday Near Naples, Magnificent Albert Sits Planning Some Clever Arrangement Keeping Calm.\n\nOk, looks crazy until you break it down;\n\nH He Li Be B C N O F Ne Na, Mg Al Si P S CL Ar K Ca\n\nThen put it into the table\n\nH\nHe\nLi Be B C N O F Ne\nNa Mg Al Si P S Cl Ar \nK Ca\n\nYou will need to line them up because Yahoo has left align, but the trick is the story. \n\nThe groups 1-8 tell you how many electrons are in the outer shell, the periods tell you how many shells etc\n\nHope this helps!