Why is it so easy for a magnesium atom to lose two electrons?
476212
Atoms want to be like a "noble gas" with a filled outer shell.  I think it has to do with being in a stable state.  For Mg, it's a lot easier to drop 2 electons to look like Ne rather than gain 6 to look like Argon.\n\nThis very basic premise only works for things on the "sides" of the table.  The transition elements in the middle are a bit different.
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.
810145
depends what the magnesium is for. If this is for a chemical reaction, it's because copper is less reactive than magnesium (it's lower on the activity series list).
511467
When two elements come together, the type of bond they from depends on the number of valence electrons.  Everybody is shooting for 8 valence electrons with the exception of couple of elements (i.e. hydrogen which is happy with 2). If the number of valence electrons is such that, it's tough for an element to lose or gain that many electrons to achive 8 valence electrons, two elements share electrons to fill their valence shill with 8 electrons and a covalent bond is formed.
187349
The chlorine ion would be much larger because Mg is a metal and Cl is a nonmetal. When ionized, metals tend to lose electrons (and a stable octet) and become smaller. On the contrary, nonmetals gain electrons (and a stable octet) and become larger.
1021964
usually the valence in an ion leaves a noble gas config (ngc) so if the it is a cation, it looses electrons to have a ngc and for an anion, it gains electrons to have a ngc.
710065
atoms of positive charge are lighter than negative.
791063
Excited state from what I know is when the electrons violate hund's rule, where the electrons occupy the subshells and fill each one individually. Like in the p orbital there are three subshells each subshell takes two electrons a piece, but they will only fill up completely if all subshells are occupied. This is because of electron repulsion for the like charges(hund's rule). But if the atom fills a subshell completely without first distributing them is when it is said to be excited. I think you'd have to add an electron to boron and have it fill the same subshell in the 2p orbital (either the x,y,or z).
787388
Basically what this is referring to is the ionization of the atoms you have listed. this occurs when there is a shift in the distribution of the electron in the various bands 'orbiting' the nucleus of the atom, or a proton has been added to the nucleus. \n\nWhat the statement seems to be refering to is the creation of a positive ion (cation). If this is to occur it needs a shift in the distribution of the electrons in the shells. To move an electron from one band to another, or to excite one enough to be lost fully from orbit you will need a level of energy. \n\nIn the cases stated, I would say that 3.1eV is the minimum energy required to create a transition of an electron between the bands or to lose an electron and so create the ion. \n\nHope that helps.
844206
The answer is simple. All elements (whose basic units are atoms) except the noble gases, have less than 8 electrons in their valence shells.  The rule that states that atoms should have 8 electrons to achieve stability is called The Octet Rule.\n\nhttp://en.wikipedia.org/wiki/Octet_rule\n\nThe way that they can attain 8 electrons is by forming BONDS: by either sharing electrons (covalent bond) or by gaining/losing electrons (ionic bond).   This is the main reason why atoms react: to attain 8 valence electrons.\n\nIf we look at it at another angle, we can say that atoms react in order to decrease energy.  This comes from the principle that bond formation results in loss of energy, and that stability comes from decreased energy.\n\nHope that helps.
175956
C, remember that the electron loses and gets energy several times through the chain.
940864
They would lose electrons.  metals lose electrons to obtain there octet.  \n\nNa, K would lose 1 electron\n\nMg and Ca would lose 2.\n\n\nwhoever said Ca would gain an electron is an idiot
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.
402942
An atom is stable when it has a full valence (outer) electron shell.  For the first row on the periodic table, the outer (and only) shell can hold up to 2 electrons.  For the next two rows, the atoms' outer shells can hold up to 8 electrons.  The next two can hold up to 18.\n\nAtoms like sodium, in column 1 of the periodic table, have one electron in its valence shell.  It is very reactive, since it wants to get rid of this extra electron so that its outer shell can be full.\n\nAtoms like chlorine, in the second last column, have one electron missing from their valence shells.  They are also very reactive, since they want to accept an electron to fill the outer shell.\n\nNoble gases are almost totally unreactive, since they have the unique property of having full outer shells without having to give away or accept any electrons.
850100
I'll do one for you and then you can try the rest.\n\nMagnesium has 12 electrons, so follow your filling order. Each s orbital holds to electrons and each p orbital holds 6, so its:\n\n1s2 2s2 2p6 3s2\n\nIt has 2 electrons in its outer shell so to have a full outer shell it will lose 2 therefore the common ion It forms is Mg2+
1058444
Mg2+ < Na+ < Br-\n\nIon size depends first on the main quantum number. Na and Mg both strip down to the Ne configuration, while Br takes up the Xe configuration, two main quantum numbers higher.\n\nMg2+ is smaller than Na1+ because the remaining electrons are subject to a stronger electrostatic field.\n\nThe above is true for ions in crystal lattices.\n\nNote that in watery solutions ion size has to be calculated differently when you take the hydrate shell into account. Na+ becomes Na(H2O)6(1+), and Mg2+ becomes Mg(H2O)6(2+). Bromide won't take up a regular hydrate shell.
783373
This depends on how many electrons the element has to lose or gain to complete its outer layer. If the element is on the right side of the periodic table then it will gain electrons. The left side will lose electrons. How many electrons can be determined by how far away the element is from the nearest side of the periodic table.\n\nTHere is of course more technical depth to this however this thumb rule will do. For more info type ionisation into wikipedia. that should help...