Assignment : Make a table enlisting first 20 elements of the Periodic Table. Write in
which state they are present at room temperature. Give one example of a
compound which is formed by each of these elements. All the compounds must be
different.
Element
State
Compound in which
this element is present
Hydrogen peroxide (HO)
1. Hydrogen
Gaseous
Answers
Answer:
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Answer:
The Elements
Elements are pure substances. The atoms of each element are chemically distinct and different from those of any other element. Approximately 110 elements are now known. By 1980, 106 of these had been unequivocally characterized and accepted by the International Union of Pure and Applied Chemistry (IUPAC). Since that time, elements 107 and 109 have been identified among the products of a nuclear reaction. The search for new elements continues in many laboratories around the world; new elements may be announced at any time.
A. Names and Symbols of the Elements
Each element has a name. Many of these names are already familiar to you - gold, silver, copper, chlorine, platinum, carbon, oxygen, and nitrogen. The names themselves are interesting. Many refer to a property of the element. The Latin name for gold is aurum, meaning "shining dawn." The Latin name for mercury, hydrargyrum, means "liquid silver."
The practice of naming an element after one of its properties continues. Cesium was discovered in 1860 by the German chemist Bunsen (the inventor of the Bunsen burner). Because this element imparts a blue color to a flame, Bunsen named it cesium from the Latin word caesius, meaning "sky blue."
Other elements are named for people. Curium is named for Marie Curie (1867-1934), a pioneer in the study of radioactivity. Marie Curie, a French scientist of Polish birth, was awarded the Nobel Prize in Physics in 1903 for her studies of radioactivity. She was also awarded the Nobel Prize in Chemistry in 1911 for her discovery of the elements polonium (named after Poland) and radium (Latin, radius, "ray").
Some elements are named for places. The small town of Ytterby in Sweden has four elements named for it: terbium, yttrium, erbium, and ytterbium. Californium is another example of an element named for the place where it was first observed. This element does not occur in nature. It was first produced in 1950 in the Radiation Laboratory at the University of California, Berkeley, by a team of scientists headed by Glenn Seaborg. Seaborg was also the first to identify curium at the metallurgical laboratory at the University of Chicago (now Argonne National Laboratory) in 1944. Seaborg himself was named a Nobel laureate in 1951 in honor of his pioneering work in the preparation of other unknown elements.
Each element has a symbol,one or two letters that represent the element much as your initials represent you. The symbol of an element represents one atom of that element. For 14 of the elements, the symbol consists of one letter. With the possible exceptions of yttrium (Y) and vanadium (V), you are probably familiar with the names of all elements having one-letter symbols. These elements are listed in Table 3.1. For 12 of these elements, the symbol is the first letter of the name.
Potassium was discovered in 1807 and named for potash, the substance from which potassium was first isolated. Potassium's symbol, K, comes from kalium, the Latin word for potash. Tungsten, discovered in 1783, has the symbol W, for wolframite, the mineral from which tungsten was first isolated.
TABLE 3.1 Elements with one-letter symbols
Symbol Element
B
boron
C
carbon
F
fluorine
H
hydrogen
I
iodine
N
nitrogen
O
oxygen
Symbol Element
P
phosphorus
K
potassium
S
sulfur
W
tungsten
U
uranium
V
vanadium
Y
yttrium
Most other elements have two-letter symbols. In these two-letter symbols, the first letter is always capitalized and the second is always lowercased. Eleven elements have names (and symbols) beginning with the letter C. One of these, carbon, has a one-letter symbol, C. The other ten have two-letter symbols (see Table 3.2).
TABLE 3.2 Elements whose name begins with the letter C
Symbol Element
Cd
cadmium
Ca
calcium
Cf
californium
C
carbon
Ce
cerium
Cs
cesium
Symbol Element
Cl
chlorine
Cr
chromium
Co
cobalt
Cu
copper
Cm
curium
B. Lists of the Elements
While you study chemistry, you will often need a list of the elements. To see a list of the elements click here. The list includes the symbol, the atomic number, and the atomic weight of the element. The significance of atomic numbers and weights will be discussed in Chapter 4. For now it is sufficient to know that each element has a number between 1 and 110 called its atomic number. This number is as unique to the element as its name or symbol.