answer this?

Question

what is the definition of valency?how can u tell the valency of an element by just looking it and what is the definition of ion???

Answer 1

Valence, also known as valency or valency number, is a measure of the number of chemical bonds formed by the atoms of a given element. The concept was developed in the middle of the nineteenth century in an attempt to rationalize the formulae of different chemical compounds. Although it has fallen out of use in higher level work with the advances in the theory of chemical bonding, it is still widely used in elementary studies where it provides a heuristic introduction to the subject

Answer 2

Valence electrons (I'm assuming you mean chemistry here) is the outermost shell of electrons. It's pretty much the outer shell that is used in most chemical reactions. Most elements like to have 8 electrons in their outer shell or "ring", making them "full" or "neutral". The first ring holds 2, and then 8, and 8 again, (going beyond the 3rd shell is 18 I believe and then more after that, but assuming you're just in intro chem you won't go that far) But basically..ok, for example, Hydrogen has 1 electron in it's outer shell. It would LIKE to have 2, so therefore it lacks 1 electron to be "complete" and full and happy. You can tell the valency of an element by looking at it's atomic number. The atomic number tells you the number of protons in the nucleus. In a stable element, meaning it has the same amount of protons and electrons, you take that number and subtract the number of electrons to make a shell. For example.... Oxygen (O) has an atomic number of 8. That means it has 8 electrons. 2 are used to fill the 1st shell, and then 6 are in the next shell. Well, those shells LIKE to have 8 right, so we say it "lacks 2 electrons to be complete".
In an ion, that means you have more or less electrons than the atomic number of protons in the nucleus. For example...Sodium (Na) atomic number is 11 (this is the number usually found above the element on the periodic table) So that means it has 11 protons in it's nucleus, now, if the electrons are less than 11, then we say it is a positively charged ion, because the charge of the protons in the nucleus (+) is more than the electrons which are negative. Say, there are only 10 electrons, that would make Sodium a +1 cation. Now, say, that Sodium had 12 electrons. Well, it's atomic number is only 11. That means it has 11 protons(+) and 12 electrons (-). There's 1 more negative than positive, right? That means it has a negative charge of -1, also known as an anion. Hope this helped.

Answer 3

Valency is the power of an element to combine with other elements like H=1, O=2 , Cl=1. We cannot tell the valency directly by looking at it however we can tell it from the electronic configuration. The no. of electrons which the element donates or accepts to become stable ( the least of the 2) is its valency. An ion is a charged particle having either +ve or -ve charge. Loss of electrons make +ve and gain of electrons make -ve ion.

Answer 4

Valency: Valence, also known as valency or valency number, is a measure of the number of chemical bonds formed by the atoms of a given element. The concept was developed in the middle of the nineteenth century in an attempt to rationalize the formulae of different chemical compounds.

http://en.wikipedia.org/wiki/Valency_%28chemistry%29

Ion: An ion is an atom, group of atoms, or subatomic particle that normally is electrically neutral and achieves its status as an ion by loss (or addition) of an electron. The simplest ions are the proton (a hydrogen ion, H+, positive charge), and alpha particle (helium ion, He2+, consisting of two protons and two neutrons).

http://en.wikipedia.org/wiki/Ion

For more information and a more detailed response, check out the links!

Answer 5

the valency of an element given by the number of electrons that it has available for 'trade' or 'link' with another element.
in order to 'tell the valency' you have a few rules:
(get a mendeleev's table right about now)
1) for elements in groups Ia, IIa and IIIa, the valency is the number of the group
2) elements in IVa have multiple valency, the most common of which are 2 and 4
3) for elements in Va, VIa and VIIa, the valency is (8 - group number; i.e. valency 3 for group Va)
4) elements in VIIIa have no valency. that's cause they're stable elements
5) for secondary groups... well there are no rules there, but most tests and something will provide the valencies.

edit: hey am i the only one that comes up with an answer on her own? this is b******t!

Answer 6

Valency is the combining power of an element (i.e. the number of bonds which the atom can form with other atoms).

Valency is governed by the number of electrons in the outermost electronic shell of the atoms of that element (i.e. the valency electrons). These valency electrons are given up to other atoms or are received from other atoms to make Ionic Bonds, or the valency electrons are shared with other atoms to make Covalent Bonds. The process of transferring electrons between atoms or of sharing electrons between atoms results in the formation of compounds, where the atoms in the compound achieve the stable electronic configuration of the Nobel Gas elements.

Answer 7

Valence is also known as valency or valency number, is a measure of the number of chemical bonds formed by the atoms of a given element.hope that helps

Answer 8

Valency refers to the capacity of a verb to take a specific number and type of arguments (noun phrase positions)- one definition, perhaps not the one you are looking for....

Valency is also the combining power of an element (i.e. the number of bonds which the atom can form with other atoms).
Valency is governed by the number of electrons in the outermost electronic shell of the atoms of that element (i.e. the valency electrons). These valency electrons are given up to other atoms or are received from other atoms to make Ionic Bonds, or the valency electrons are shared with other atoms to make Covalent Bonds. The process of transferring electrons between atoms or of sharing electrons between atoms results in the formation of compounds, where the atoms in the compound achieve the stable electronic configuration of the Nobel Gas elements.

In order to achieve the electronic configuration of the nearest inert gas, which is a stable electronic configuration, atoms may lose, gain or share electrons. When these valency electrons are given up by an atom, or are received by an atom, to make ionic bonds are formed. When these valency electrons are shared with other atoms, covalent bonds are formed. Thus, the electron transfers result in the formation of bonds between atoms, and in the formation of compounds.

In general, the normal valency of an atom is thus equal the smaller of the following two numbers:

its periodic group number, or

eight minus its group number.

However, a number of elements show more than one valency. Thus, the valency displayed by an element in any particular compound depends on its oxidation state in that compound.

An ion is an atom, group of atoms, or subatomic particle that normally is electrically neutral and achieves its status as an ion by loss (or addition) of an electron. The simplest ions are the proton (a hydrogen ion, H+, positive charge), and alpha particle (helium ion, He2+, consisting of two protons and two neutrons).

Answer 9

valency is the power of an atom of an element to combine with other atoms measured by the number of electrons which an atom will give, take, or share to form a chemical bond. This is related to the number of spaces left in an atom's electron shells

Ion: An atom or group of atoms that carries a positive or negative charge as a result of having lost or gained one or more electrons.

Answer 10

the charge carried by the atom is valency
its very easy to find out
letme teach you
you have to know the charsge carried by the atom
the magnitude of charge will give u valency

other wise .know the atomic number of the element
see how much electrons it needs to get stable configuration
that is to get.,2 or10 or 18 or 32 or so on

let me give yu examples
in HCL , it is H+ and CL- therefore valency is 1
in CASO4 it is ca2+ and SO4 2- means tha valency is 2

atomic number of oxygen is 8 . it needs 2 more electrons to become 10]
therefore its valency is2