what is the ionization energy of selenium?
479233
The energy of the incoming photons is given by Planck's relationship:  energy = Planck's constant * frequency.\n\nYou are given the wavelength, not the frequency, so you need to know that for any wave, the wavespeed = frequency * wavelength, so frequency = wavespeed/wavelength.  For photons, wavespeed = c.\n\nh = 6.626068 × 10^-34 34 m^2 kg / s (Planck's constant)\nc = 2.998 × 10^8 m / s (speed of light)\nwavelength = 48.2 x 10^-9 m (given in problem)\n\nPutting this together, the energy of each incoming photon is:\n\nE_photon = h*c/(48.2 x 10^-9 m) = 4.121 x 10^-18 J\n\nThe outgoing electron has kinetic energy = 1/2 * m * v^2.  You are given both m and v:\n\nE_electron = 1/2 * 9.109 x 10^-31 kg * (2.371 x 10^6 m/s)^2 \nE_electron = 2.56 x 10^-18 J\n\nThe ionization energy is the difference in energy between the incoming photon and the kinetic energy of the outgoing electron.  Because the question asks for the energy in joules per mole, we must multiply the energy difference for a single photon/electron pair by Avagadro's number:\n\nE_ionization = (E_photon - E_electron)* N_A\n\nE_ionization = (4.121 x 10^-18 J -2.56 x 10^-18 J)*6.022 x 10^23 mol^-1\n\nE_ionization = 9.4 x 10^5 J/mol = 940 kJ/mol
803831
14 of each\n\nhttp://www.webelements.com/webelements/elements/text/Ag/ionz.html
903602
Since Se is located below sulfur and oxygen in the periodic table, its ion would probably have a charge of -2.
192380
http://www.webelements.com/webelements/elements/media/kossel-pics/Xe.jpg\nYou can find that:\n1st shell: 2 electrons\n2nd shell: 8 electrons\n3rd shell: 18 electrons\n4th shell: 18 electrons\n5th shell: 8 electrons\nGround state electron configuration:  [Kr].4d10.5s2.5p6 \nShell structure:  2.8.18.18.8 \nTerm symbol:   1S0
712728
choose the noble gas that comes before the element.   in Mn(2+)'s case, that's Ar\n\nwrite the noble gas down in brackets, and continue on with the electron config. as normal\n\n[Ar}4s23d3\n\nFor O(2-), it turns into Neon so it would just be [Ne]
919041
We're basically looking for a ratio of ionization energy E(n), where n =4 and n = 1 (ground state). Electron energy levels of a hydrogen atom is given by:\n\nE(n) = 13.6/n^2 eV\n\nTherefore,\n\nE(4)/E(1) =  1/16\n\nIt takes only 1/16 of 13.6 eV , or 0.85 eV, to ionize the ground state electron from a hydrogen atom on this very hot planet.
1089354
Whatever its atomic number is, would be the number of electrons. If it's an ion, then add for every negative value and subtract for every positive one.
140269
Mecury doesn't "lack one electron".  What you would need to do is remove one proton from mercury to make it into gold, in some kind of nuclear reaction.  Now, while not impossible in theory, I don't know of any nuclear pathway to do it, and it would no doubt be prohibitively expensive to do if there were.
421381
Several Units actually and they can be a bit confusing\n\nRad, Rem, Seiverts, grey, etc etc\n\n\nhere is the break down\n\nKerma = Kinetic Energy transferred to charged particles in Rads / Grays.\nRad = radiation absorbed dose\n= 100 ergs of energy / gm of tissue\n= 0.01 joule of energy / kg of tissue\n1 Gray = 100 Rads = 1 joule of energy / kg of tissue\n1 Rad = 0.01 Gray\n1cGy (centi Gray) = 1 Rad\n1 mGy (milli Gray ) = 0.1 Rad\nRem = radiation equivalent man\n= rad x RBE (QF) / (relative biological effectiveness or Quality factor)\nSeivert = Gray x QF\n1 Seivert = 100 rems \n(1000 milliSv or mSv)\n1 mSv = 0.1 rem ( for Xrays which have a qualifying factor of 1) = 1 mGy\n\n\n\nconfusing huh?  took 2 college terms on it myself
511125
Its either d or e. It should be a deshielding effect by the pi electrons. There is some gobbledy-gook showing up in my browser so I can't tell d or e is the pi symbol.
62273
Arsenic has exactly 3 electrons in its 4p orbitals, meaning exactly one electron in each orbital.  This is extremely stable, and takes extra energy to dusturb.  Conversely, Se has four in the 4p orbitals, meaning one extra--by losing this, it gets the more stable configuration acheived by neutral As.  the stability of the Se ion makes the required energy less, and this explains the local reversal of the ionization energy trend moving left to right.
414002
one cannot measure electronegativity.it has been given on the Pauling scale given by Pauling .and charge can be determined by the valency of the element.
271464
Sodium has a greater ionization energy than potassium becuase as you go down a group the ionization energy decreases. This is becuase the outer electrons that are being added are further away from the control of the nucleus and take less energy to remove.
594430
Selenium is an element, with symbol Se.  Atomic number 34, atomic mass 79.  In neutral state, has the electronic structure 1s2,2s2,2p6,3s2,3p6,4s2,3d10,4p4.  Can form both covalent compounds, where it can be either the central atom or not, or can ionize, usually to the -2 state, to form salts.
841087
Se has the electron arrangement 4p4. One of the 4p orbitals will be full holding 2 electrons.\nTwo of the 4p orbitals will have one electron each in - ie half full
258486
This is a more complicated question than it appears.  You didn't include to what degree you were seeking this information, so rather than go into a great deal of explanation I have included a link that explains and tabulates the basics of electron energy levels.  Hope this helps.
774337
An electron has the greatest (ionisation) energy in the energy level n = 1.\nAn electron cannot occur between energy levels, unless it is moving from one to the other.