why does hydroxide have a negative charge?
108088
The Hydroxide ion has a negative 1 charge due to the fact that the over all ion has an extra electron.\n\nOxygen needs two additional electrons to fill its octet.  Bonding with the Hydrogen provides Oxygen with one, the other electron is picked up from somewhere else to make the over all ion have a charge.
763345
Let's say you want to know what is the formula of Aluminum oxide.\n\nYou know that oxides always have a negative 2 charge and Aluminum is always a positive 3 charge.  So if you have 2 positive 3 charges that would be a positive 6, and if you had 3 negative 2 charges that would be a negative 6 and that would allow the charges to cancel out to a zero.\n\nSo the formula would be Al2O3 for aluminum oxide.\n\nIn other words, the criss cross method of determining the formula uses the charge of the opposite ion to determine how many atoms to use.  It criss crosses.
589096
Polar molecules, such as water molecules, have a weak, partial negative charge at one region of the molecule (the oxygen atom in water) and a partial positive charge elsewhere (the hydrogen atoms in water). \n\nThus when water molecules are close together, their positive and negative regions are attracted to the oppositely-charged regions of nearby molecules. The force of attraction is called a hydrogen bond.
788550
The only other way I know of is to know the formula of a compound or ion/radical containing that element, and use the following rules:\n1. Total for all elements in a compound must be 0. Total for an ion is the charge on the ion.\n2. First element in a compound is always (+); last element in a compound is always (-). (Not necessarily true for ions: Hydroxide ion OH- has O -2 and H +1; I believe it's true for all other ions/radicals but not certain.)\n3. H is always +1 or -1.\n4. O is almost always -2, unless it's -1 or +2 because of one or more of the above rules. (Example 1: Oxygen molecule O2 has one +2 and one -2; Example 2: Hydrogen peroxide H2O2 has two H +1 and two O -1.)\nIn fact, oxidation number doesn't mean much unless it's in the context of a compound. As above, oxygen atom can be either -2, -1 or +2 depending on the compound it's in. In fact, a molecule with two or more oxygen atoms can even have its oxygen atoms in different oxidation states!
710065
atoms of positive charge are lighter than negative.
812222
The size is decreasing as you go across that list.  A rough rule of thumb is "The more positive the charge, the smaller the ion."   (The reverse is true, too...the more negative the charge, the larger the ion.)
1050318
With any ion - you can look at the charge it has to determine how many extra electrons it has.\n\nFor example -  elemental Sulfur has 16 electrons. To have a negative 2 charge it must have gained an additional 2 electrons. So it has a total of 18. \n\nBut since 18 is not one of the answers I assume the answer is 2 because it gained 2 electrons to get the negative 2 charge.\n\nHope this helped!
860471
H has an oxidation number of +1\nPO4 has an oxidation number of -3.\nIt doesn't make sense to talk about the oxidation number of the whole compound.
283437
Sodium Hydroxide dissolves in water and dissassociated completely to form Sodium +1 and Hydroxide -1 ions in solution.\n\nNaOH --H2O--> Na+(aq) + OH-(aq)
168285
Some elements have differing soluability depending on their oxidation state.  If the hydroxide of one oxidation state is insoluable but another oxidation state is soluable, then it would act as a test for oxidation state.\n\nAnother possible way for sodium hydroxide to act as a test for oxidation state is if the element in question has different colors in different oxidation states in basic pH.
129468
It's a negative or positive charge that is used to repel oppisite forces
820135
it depends on the medium the H-Cl is in.\n\n---------------------------\n\nin its pure gaseous form, there is no charge on either H or Cl.  It is just a covalent bond.  Because Cl is considerably more electronegative than H, this covalent bond is polar, giving a partial positive charge to the H and a partial negative to the Cl.\n\nif you dissolve H-Cl in water, then the water splits (solvates) the H-Cl into its ions, H+ and Cl-, thus giving H a plus 1 charge and Cl a minus 1 charge.
404745
The "p" stands for negative log.\nSo, the negative log of the concentration of H+ ions in solution gives you the pH.  \n-log[H+] = 3.40\nMultiply both sides by negative one:\nlog[H+] = -3.40\nNow raise 10 to the both sides.  This will cancel out the log function. \n10^log[H+] = 10^-3.40\n[H+] = 3.98E-4 M\n\nTo get the [OH-], just divide the [H+] into 1.00E-14:\n1.00E-14 / 3.98E-4 = 2.51E-11 M
486231
NaOH is ionic.\n\nAll has to do with electronegativity and the difference between the two species bonded to each other.  If the electronegativity difference is less than 0.5, the bond is considered to be fairly non-polar.  Between 0.5 and 1.5 is usually a polar bond, greater than 1.5 usually means that there will be charge separation and the bond will be ionic.\n\nFor either polar or non-polar bonds, you need to know the geometry of the molecule and determine whether the sum of the individual dipoles in the molecule will cancel (vector sum).  If they do, the molecule is non-polar.  If they don't, it is.  For instance, water is polar as its polar bonds do not cancel geometrically, but CH4 is non-polar, even though each of its bonds is polar.
495744
Well, if you run a current through saltwater (NaCl in water solution), two half-reactions are taking place in an electrolytic cell: \n2Cl- ---> Cl2 + 2e-  anode, oxidation (+)\n2H20 + 2e- ---> H2 + 2OH-  reduction, cathode (-)\nThe negative end is producing H2 gas, which bubbles out of solution, and hydroxide ions, which are basic.  So the stuff coming off of the negative end is basic, not acidic.
541170
New in Chemistry?????\n\nThere is no conversion of H2O in HHO.\nIt is simply way of writing a formula. HHO is wrong, it is HOH.\n\nActually Oxygen has two separate bonds with two different atoms of Hydrogen so it is written as H-O-H.\n\nWhen H-O-H is broken it usually converts to H+ and OH-
570619
no this is incorrect\n\nsodium hydroxide will ionise in water to produce sodium+ ions and Hydroyl (-ve) ions\nso\n\nthewater is not truely a reagent in this reaction,  it is simply the solvent\n\nNaOH + H2O -> Na(+)aq + OH(-)aq\n\nthe aq after an ion indicates it is in aqueous solution (ie in water\nions charges should be written in superscript after the ion (ie above and after) - not in brackets