Can you please explain thoroughly to me about all this.
Why do we criss cross the formulas of compounds?
How do we find out which combining capacity to use if there are more than one? Is there a special formula we use to find out or something? I really do not understand.
Criss cross to obtain the formula of a compound is a simple technique working out the formula. In a formula, the + charges must equal to the negative charges because compounds are neutral. IN Fe2O3, for example, the 2*+3 for Fe = 3*-2 for oxgen and +6 - 6 = 0.That kind of calculation can be done every time a formula is needed; however, criss crossing is a simpler method of obtaining the same thing. If we write +3 above the iron and -2 above the O atom, we obtain Fe2O3 if we criss cross those numbers (we ignore the signs) AND if we obtain numbers that are multiples we usually reduce to the smallest set of numbers. For example MgO we would write +2 above Mg and -2 above O which would give us Mg2O2 which we reduce to MgO.
I don't know of any way to know for sure about the combining capacity when more than one is available. Iron forms so many +2 and +3 compounds; experience helps but I've had years of experience and sometimes I'm not sure either.
Thank you, I'm kind of getting it. I am developing some understandings on this topic. Thank you very much for the information:-)
Certainly! Let's start by understanding why we criss cross the formulas of compounds:
Criss crossing the formulas of compounds is a method used to determine the combination of elements and their ratio in a compound. It is based on the concept of ionic bonding, where positive and negative ions attract each other to form a compound.
In an ionic compound, the formula represents the simplest whole-number ratio of the ions present in the compound. Here's how the criss cross method works:
1. Identify the charges of the ions: Each element in the compound forms an ion with a specific charge. For example, sodium (Na) forms a +1 ion, and chlorine (Cl) forms a -1 ion.
2. Criss cross the charges: To determine the subscripts of each element in the compound, criss cross the charges. The positive charge of one ion becomes the subscript of the element with the negative charge, and vice versa. For example, Na+1 and Cl-1 will criss cross to form NaCl, which is the formula for sodium chloride.
The criss cross method ensures that the overall compound is electrically neutral since the charges of the ions cancel out.
Now, let's move on to how to find out which combining capacity to use if there are more than one:
To determine the combining capacity (or combining power) of an element, you need to consider its valence electrons. Valence electrons are the electrons in the outermost shell of an atom, which are involved in chemical bonding.
The combining capacity is typically represented by a number or a Roman numeral in parentheses following the element's symbol. It indicates how many bonds an element can form or how many electrons it can accept or donate during a chemical reaction.
One way to determine the combining capacity of an element is by referring to the periodic table. The group number of an element on the periodic table usually corresponds to its combining capacity. For example, elements in Group 1 (such as Na) have a combining capacity of +1, while elements in Group 17 (such as Cl) have a combining capacity of -1.
In some cases, the combining capacity of an element may vary depending on the compound it forms. In such cases, if you know the oxidation state of the element in the compound, you can use that information to determine the appropriate combining capacity.
It's important to note that the combining capacity is not a fixed property of an element. It can change depending on the specific compound or reaction.
So, by using the criss cross method and understanding the combining capacities, you can determine the formulas and ratios of compounds.