Ionic Essay Example

Ionic Essay Define and describe ionic and covalent bonds. An ionic bond is a type of chemical bond formed through an electrostatic attraction between two oppositely charged ions. A covalent bond is the chemical bond that involves the sharing of pairs of electrons between atoms. A compound is made when two or more atoms form a chemical bond, linking them together. The two types of bonds are ionic bonds and covalent bonds. In an ionic bond, the atoms are bound together by the attraction between oppositely charged ions. If the electron is shared equally between the atoms forming a covalent bond, then the bond is said to be nonpolar. An electron is more attracted to one atom than to another which forming a polar covalent bond. Ionic bonds are formed between a cation and an anion. Pure ionic bonding cannot exist: all ionic compounds have some degree of covalent bonding. An ionic bond is considered a bond where the ionic character is greater than the covalent character. The larger the difference in electronegativity between the two atoms involved in the bond, the more ionic the bond is. Bonds with partially ionic and partially covalent character are called polar covalent bonds. Ionic bonding is a form of no covalent bonding. We will write a custom essay sample on Ionic specifically for you for only $16.38 $13.9/page Order now We will write a custom essay sample on Ionic specifically for you FOR ONLY $16.38 $13.9/page Hire Writer We will write a custom essay sample on Ionic specifically for you FOR ONLY $16.38 $13.9/page Hire Writer Ionic compounds conduct electricity when molten or in solution, but not as a solid. They generally have a high melting point and tend to be soluble in water. The stable balance of attractive and repulsive forces between atoms when they share electrons is known as covalent bonding. For many molecules, the sharing of electrons allows each atom to attain the equivalent of a full outer shell, corresponding to a stable electronic configuration. Covalent bonding includes many kinds of interaction, including ? -bonding, ? -bonding, metal-to-metal bonding, agnostic interactions, and three-center two-electron bonds. The term covalent bond dates from 1939. The prefix co- means jointly, associated in action, partnered to a lesser degree in essence, means that the atoms share valence. Molecule H2, the hydrogen atoms share the two electrons via covalent bonding. Covalency is greatest between atoms of similar electronegativity. Covalent bonding does not necessarily require the two atoms be of the same elements, only that they are of comparable electronegativity. Although covalent bonding entails sharing of electrons, it is not necessarily delocalized.

How to Analyze a File Line By Line With Python

How to Analyze a File Line By Line With Python One of the primary reasons people use Python is for analyzing and manipulating text. If your program needs to work through a file, it is usually best to read in the file one line at a time for reasons of memory space and processing speed. This is best done with a while loop. Code Sample for Analyzing Text Line by Line fileIN open(sys.argv[1], r) line fileIN.readline() while line: [some bit of analysis here] line fileIN.readline() This code takes the first command line argument as the name of the file to be processed. The first line opens it and initiates a file object, fileIN. The second line then reads the first line of that file object and assigns it to a string variable, line. The while loop executes based on the constancy of line. When line changes, the loop restarts. This continues until there are no more lines of the file to be read. The program then exits. Reading the file in this way, the program does not bite off more data than it is set to process. It  processes the data it does input faster, giving its output incrementally. In this way, the memory footprint of the program is kept low, and the processing speed of the computer does not take a hit. This can be important if you are  writing a CGI script that may see a few hundred instances of itself running at a time.   More About While in Python The while loop statement repeatedly executes a target statement as long as the condition is true. The syntax of the while loop in Python is:   while expression: statement(s) The statement may be a single statement or a block of statements. All the statements indented by the same amount are considered to be part of the same code block. Indentation is how Python indicates groups of statements.