Using principles of atomic structure,expla... why Na ion is much smaller than K ion ?[explain both]?
491001
Homework, huh?\n\nWell, it's because K+ contains more electrons than the Na+. Which means that K+ has 3 layers of electrons (filled in the 1s2 2s2 2p6 3s2 3p6) while while Na+ has only 2 layers of Electrons (1s2 2s2 2p6)
921116
I'm not directly giving you the answers, you have to know how to do this stuff, but I'll give you the process to get to each.\n\n9: Americium and Curium (wikipedia!)\n\n10: Potassium ion wants to be like the noble gas closest to it (the one right before it), so it loses 1e- to get there and be K+.  If that's not a choice, then look for another ion, positive or negative, that adds up to the electronic configuration of the aforementioned noble gas. (1s2 2s2 2p6 3s2 3p6), 18 total e-'s...\n\n11: Mg is in column 2, things in the same period tend to be chemically similar.  Find the other one in the choices that's in that column\n\n12: U235 and U238 are isotopes, same atomic number, different weight.  If you change the number of protons, you change the atomic number, so that wouldn't be U anymore.  Changing electrons can make ions, but not change weight.  So different number of neutrons for the same element makes an isotope.\n\n13: Same explanation as above, it'll also be Hydrogen's atomic number because it's an isotope.\n\n14: shell 2 contains the 2s and 2p subshells.  2s can hold 2 because it's an s orbital.  2p can hold 2 per p orbital, and a p subshell has 3 p orbitals, so 6.  Total would then be...\n\n15: If an atom loses electrons, it's LOSING -1 per electron lost, so it's becoming more positive.\n\n16: Which element in that list only has 1s shell? Which one has a  stable ion as just a proton or with a configuration like Helium (1s2)?\n\n17: Inert elements are on the far right of the periodic table.  They are inert because they have 8 valence (outer shell) electrons (or 2 in Helium's case) so they can't take anymore and are stable.  Look at your periodic table or count up electrons for each of those atomic numbers.  Only one of them will have 8 in the outer shell...
370118
if it forms a 2- ion it is from the Chalcogen (group V1(A) or 16) family (Oxygen, Sulphur, ...).  The two bonds between two Oxygen atoms are Covalent.  It has 6 valence electrons and takes two to complete the valence shell (noble configuration).\n\nThe reaction of X with Sodium (Na) will require twice as many Na atoms as Sodium only has 1 valent electron to give (to make the Na+ ion)\n\nSo\n\n2Na + X -> Na2X which in a polar solvent (e.g. water) will become 2Na+ +X2- \n\nFYI, the Halogens are Fluorine, Chlorine etc and only have one single space left to take an electron to reach Noble configuration hence they form singly charged anions F-, Cl-...
482712
um...  subtract???  hahaha\n\nThe higher the differences in electronegativity, the more ionic the compound.  The higher electronegative atom/ion will want to "hog" all the electrons.  They are greedy like that.  They don't want to share (which would be a covalent bond).
983381
sodium ions are one short in electrons than the sodium atoms while number of protons remain the same .Hence the nucleus exerts extra attractive force on the electrons resulting in the shrinking of the size of the ion.
953247
the previous answer is deficient on the following points...\nelemental C has the atoms held together by covalent bonding\nNa, being a metal, has metallic bonding, not ionic. Ionic bonds occure BETWEEN a metal and a non metal such as Na with Cl.\nMetallic character decreases as you cross the periodic table, and increases as you go down the periodic table, so Na is more metallic than Fe\nnon metallic character does the opposite..\nSo from the list above, metallic character would be Na > Fe >C  > S > O\nNa is a metallic lattice while O2 exists as discrete molecules\nHope that helps
798559
positive ions are formed by removing electrons from the atoms and hence the ionic radius for positive ion is always less than that of atomic radius
556249
In Be and Mg only the s subshell is full while the p is completely vacant. Moreover for every element the most stable state is tht of the nearest noble gas configuration. So for Be and Mg it will be quite easy to give to 2 electrons to get the nearest noble gas configuration to make stable cations. Hence they are not inactive/inert. Also they can gain electron pairs in the p-subshell (although it is energetically not favourable) so they can not be inert.
125823
The Potassium atom is larger than the Bromine atom.\nThe etra protons in the nucleus pull in electrons in the outer shell more in Bromine.\n\nThe periodic trend of the size of atoms gets larger as you go down and to the left.  Atoms get smaller as you go up and to the right.
263837
A Magnesium atom has 1 extra electron than Sodium, but this extra electron is going into the same electron shell as Sodium's (the 3S orbital), so Magnesium isnt getting any larger.  In fact, because of Mg's extra 1 proton, it actualy gets smaller since the nucleus is pulling the electrons in closer.\n\nCalcium is the next element down in the column on the periodic table.  Following the trend, Calcium will be much larger than Mg since it has an entire 8 extra electrons in two additional orbitals.  The size of the atom is greatly determined by how many electrons and in how many orbitals there are away from the nucleus.
464975
If you mean NaCl (letter L at the end instead of number one), then, yes, sodium chloride is an ionic compound. In solid form it is NaCl(s), commonly known as table salt.\n\nIn case you're wondering, the formula NaCl is actually considered a "formula unit" rather than a "molecule." In solid form, ionic compounds are 3-D matrices of ions. But when dissolved or solvated in water, the ions become free floating Na+ and Cl- ions rather than individual NaCl units. A formula unit simply shows the lowest whole-number ratio of cations (positively charged ions) to anions (negatively charged ions) given by the formula. Sodium chloride's cation to anion ratio is one sodium cation Na+ per chloride anion Cl-, or 1 to 1.\n\nBy way of contrast, the formula H2O (for water) represents a molecule, because each molecule of water is a distinct unit.
252404
An element is reactive because it is unstable.By reacting with other substances it tries to become stable.\nin case of metals or as u say positively charged elements,say,Li,Na,K...the atomic size is increasing on going down.As the size increases the the nuclear pull for the valence shell decreases,thereby making it easier to lose electrons.Thus,K easily loses electrons as compared to Na or Li and is therefore more reactive.\nin case of negatively charged atoms or non metals,the atomic size is again increasing for eg in case of F,Cl,Br..\nbut the case is opposite here.\nthe atom has to gain one electron in order to become stable.\nthe smaller the atom the more is the nuclear pull for the incoming electron and more readily it is accepted.\nthus in this case,reactivity decreases down the group.
745401
There are two rules to use:\n1) The lattice energy between ions of opposite charge is strongest when the ions are small.\n2) The lattice energies  increase rapidly as the charge on the ion becomes larger.\n\nThe first rule implies that  LE(PbF2) > LE(PbCl2), in absolute value.\nThe second implies that   LE(PbF4) > LE(PbF2) and  LE(Pb2O3) > LE (PbF4)\nTherefore we have  LE(Pb2O3) > LE (PbF4) > LE(PbF2) > LE(PbCl2)  still in absolute value.\n\nConclusion:  3c 2d 1a 2b
976855
Ions are basically charged atoms. The formula of an ion can be found out if you have the valency of the atom. You can figure out the valency of any atom by finding the group at which the atom is located in the periodic table. For example, Sodium (Na) is located in group 1A of the periodic table. Hence the valency is +1. The formula of the sodium ion would be Na+1.\n\nHope that helps!
496377
Mendeleev's work in developing a periodic table showed that similarities among elements appeared with a certain regularity. As chemists developed ways to learn about the structure of atoms, it became apparent that this regularity could be explained on the basis of the arrangement of the electrons in atoms, especially the number of electrons most distant from the nucleus.\n\nThe arrangement of electrons helps explain the formation of different kinds of chemical bonds. Some bonds result from the donation of one or more electrons from one atom to another atom in the compound.Bonds of this type are called ionic, and compounds with bonds of this type are called ionic compounds. The component parts of ionic compounds are called ions. For example, sodium chloride is an ionic compound formed when electrons from sodium atoms move to chlorine atoms.The sodium atom is converted into a sodium ion with a positive charge.The chlorine atom is converted into a chloride ion with a negative charge.\n\nCovalent bonds are formed when electrons from two or more atoms are shared. Compounds formed in this way are called covalent compounds. Carbon tetrachloride is an example of a covalent compound. Four chlorine atoms surround a carbon atom. Each chlorine atom shares one of its electrons with the carbon; and, conversely, the carbon atom shares its electrons with the chlorine atoms.\n\nIn metals, the atoms are closely packed together in rows and layers. These rows and layers explain why metals are easy to bend. The loosely-bound outer electrons in metal are shared among many atoms, creating a ìseaî of negative charges holding the metal ions in place. This is called metallic bonding. The type of bonding, whether ionic, covalent, or metallic, determines the properties and the ways in which we use substances!\n\nChemical reactions occur when the atoms are taken apart or rearranged. Energy is conserved in such reactions;that is, the energy of the reactants is equal to the energy of the products.\n\nChemical reactions proceed at different rates. Some, such as the rusting of iron, proceed slowly. Others, such as the burning of methane gas, proceed rapidly. Temperature, surface area, air pressure, and the presence of moisture or catalysts are all conditions that affect the rates of chemical reactions. Catalysts are substances that increase the rate of a reaction but are not changed themselves when the reactions are complete.\n\nHuman understanding of these principles of chemistry has enabled us to make hundreds of thousands of useful products, which enhance our lives greatly.
751854
It does completely. High melting points arise when the atoms of a substance interact and form strong inter-molecular bonds. These are weaker than ionic bonds and covalent bonds but work on the same principle. If the distance between the two atoms is great, the bond strength is low and vice versa. Thus, since potassium has a larger atomic radius, the inter-molecular bonds are weak and it is easier to melt a sample of potassium.
362157
Atomic radii decrease as one moves from left to right across a period and while moving up a group. The atomic radius is the distance between the nucleus and the valence electrons.\n\nElectron affinity, ionization energy, and electronegativity increase as one moves from left to right across a period and while moving up a group. \n\nElectron affinity is the ease with which an atom can accept an electron. The halogens (F, Cl, I, etc.) have the highest electron affinity, with F having the highest of all elements. The alkaline metals (Li, Na, K, etc.) have the lowest electron affinity, with Fr having the lowest of all elements.\n\nIonization energy is the energy needed to remove an electron from an atom. All atoms want to form a stable octet. Since alkaline metals only have one valence electron, it takes very little energy to remove an electron from them. In contrast, it takes a lot of energy to remove an electron from a halogen.\n\nElectronegativity is the strength of the attraction an atom has for an electron in a chemical bond. Halogens are the most electronegative, while the alkaline earths are the least. The electronegativity of two elements can inform you of what type of chemical bond they will form. If Na (low EN) and Cl (high EN) form a bond, Cl will rip the lone valence electron away from Na, forming an ionic bond. If C and O form a bond, the atoms will share electrons because their EN's are very close. Since O is more EN, it will have a slight negative charge, and the bond will be a polar covalent bond. If C and C form a bond, both have the same EN, and they will form a non polar covalent bond.