what makes one element different from anouther?
412159
Elements differ primarily by number of protons.  An atom containing one proton, for example, is always called hydrogen.  Protons are contained in the nucleus along with neutrons.  Electrons "orbit" the nucleus  ("orbiting" isn't a correct way to describe the electron quantum mechanical sense, but it's more-or-less helpful to think of it this way).  Protons have a positive charge, electrons a negative charge and neutrons a neutral one.\n\nElements may also vary within themselves.  Some forms of elements have more neutrons than others.  These are called isotopes of each other and have different masses.  They're referenced by their mass numbers such as "Carbon-14" or "Carbon-12".  Here Carbon-14 has two "atomic mass units" (amu) more mass than carbon 12.  Each proton and each neutron contributes one amu to the mass so carbon 1-4 has two more neutrons than carbon-12.\n\nElements may also vary by electronic species.  When neutrally charged, the same number of electrons "orbit" the nucleus as there are protons in the nucleus.  Sometimes atoms either gain or lose some electrons to become negatively or positively chaged overall (as opposed to neutral where the positive proton charges cancel exactly the negative electron charges).  These are called "ionic species" or simply "ions".
730330
Different chemical composition, one has a reaction the other doesn't..☺
570227
Na is larger than Na+.\nF is larger than F+.\nCations are always smaller than the parent atom as the effective nuclear charge acting on an electron increases as the total number of electrons decreases.\nIn the case of Na&Na+,Na+ has one whole shell lesser than Na.
232753
An atom is the smallest divisible partical that can exist on its own. Its divisibble because it contains three subatomical particals known as protons, neurons, and electrons while an element is a substance that cannot be split into two or more substance like the periodic table has a list of different elements, so examples of elements are those on the periodic table and atoms make up matter.
961656
the proton\n\nelements with different amounts of neutrons are isotopes of the same element and elements of different amounts of electrons are ions of that element. only if you change the number of protons will you have an different element.
1061455
well, thats the thing... the only way to prove that they're all different is to check every single one since the dawn of time. and they melt instantly, so you cant check them. theres not any proof that they're all different. i dont know where that idea comes from.
45574
a) Sr, Mg, Be \nRationale: they are all in the same group (II), but because Sr has the most energy levels, it has greater shielding and lower effective nuclear force, so it is easiest for it to give up an electron.  Be has the lowest number of energy levels, so it has less shielding and greater effective nuclear force, so it clings to its electrons more, requiring greater force to take away an electron.  \nb) Cs, Ba, Bi\nRationale: They are all in the same period, so shielding and effective nuclear force are not variables.  Instead, we look at stability.  Cs is in group one, meaning that it only needs to lose one electron to reach a stable octet.  The electron configuration of Bi gives exactly 1 electron per p orbital (try writing it out), so it's somewhat stable already; taking away an electron would mess with that stability.  Ba is somewhere in between.  \nc) Na, Al, S\nRationale: group I elements always have lower ionization energies in the same period because they only have to lose one electron, so sodium goes first.  Next is aluminum, which only has to lose one electron to be totally rid of electrons in its p orbitals.  Last is sulfur, which will lose one electron to have one electron in each of its p orbitals, which is less stable than the other two.
1059660
since a "certain" soft metal on burning produces lime  lime cannot be an element . hence the answer is 'c'\nanswer : 'c'\n  note: the soft metal is calcium
170267
An atom is the smallest unit of any observable thing you can have. Atoms make up almost everything we can see.\n\nIt's name is Greek for 'Indivisable' but we have since found that atoms are made of protons, neutrons and electrons (and the first two are made of even smaller particles).\n\nAn element is a substance that is entirely comprised by only one type of atom. Gold, Tin and Oxygen are elements because they are made entirely of Gold, Tin and Oxygen atoms.\n\nMolecules and Compounds are similar in that they are made up of two or more atoms of different elements in a precise and defined ratio. Atoms in compounds can be ionically bonded. Molecules are, generally, covalently bonded.
590559
(a) Across the row (called the Period), the magnitude of the 1st IE increases. At the stage where we label an element as a non-metal, this value is too high for the outermost electrons to be lost, so instead of Oxygen with a charge of 6+, it actually gains electrons to obtain the stable structure; i.e. oxygen with a charge of 2-.\n\n(b) Down the group, the size of the atom increases due to an increase in the number of shells. Due to this the outermost electrons (-ve) are further away from the nucleus (+ve) and so the 1st IE decreases.
326779
Element is the purest, single form of chemicals, ie Iron-Fe, Oxygen-O, Hg...\nCompound is the result of the reaction of different chemicals, ie Carbon dioxied CO2... Sometimes gases of one element can be called compound, ie Hydrogen-H2...\nMixture is the combination of two or more chemicals, in which the reaaction does not take place. For instance, Iron-Fe and Copper-Cu can be mixed together, but they would not react to each other.\nBase Salt - mostly is NaCl, CaCl2... - Compound\nStainless Steel - mixed between Iron-Fe, Lead-Al and others - Mixture\nTap Water - assume it is pure H2O - Compound\nTable Sugar - usually is C6H12O6 or C8H12O11 - Compound\nVanilla Extract - another result of sugar formular - Mixture of Compounds\nButter - result of processing milk - Mixture of Compounds
881836
I don't think you can choose one or the other.  Small atoms do have less of a shielding effect, but the other factor to consider is the number of protons in the nucleus.  As atoms increase in atomic number, the number of protons increases but so does the number of electrons around the nucleus, which results in the shielding effect.  Generally, as you move up and to the right of the periodic table, atoms tend to have a higher electronegativity (a measure of their ability to attract electrons).
597810
To be a homogenous a mixture must be the same throughout.  If you are only having 29 protons in the nucleus, then it is only one element.  Element number 29 is copper.  Try some nice copper wire.  Common and chemical names are both "copper".
728320
Um...one doesn't "make" mercury--it's an element.
785386
Because the number of protons is different from the number of electrons.\n\nFor example, the uranyl ion has a total of one hundred eight protons and one hundred six electrons.
1076496
Transition elements have some anomolous properties . The transition shows horizontal similarity and they have variable valencies. Instead of the gradation in properties, they show variety in properties. The groups like lanthanides and actinides are separated from the transition metals due to their unique properties. The transition elements includes differents  group of elements with  unique properties
320147
differently from what?