Classification of Elements Flashcards
Size of an atom
1.2 A°
Basic unit of all matter
Elements
In 1800, only ____ elements were known
31
By 1865 ____ elements were discovered.
More than 63
At present ___ elements are known
118
Why do we need to classify elements
•There are a huge number of elements discovered and yet to be discovered.
•To rationalize the known chemical facts about elements.
•Predict new elements along with their properties to further the studies.
The German chemist,_____ in
early 1800’s was the first to consider the idea
of trends among properties of elements.
Johann Dobereiner
Law of triads was proposed in the year
1829
Who,in which year arranged the then known elements in order of
increasing atomic weights and made a
cylindrical table of elements to display the
periodic recurrence of properties?
French geologist,
AEB de Chancourtoise in 1862.
Who,in which year proposed law of octaves?
The French chemist,John Alexander Newlands in 1865.
Which classification resembles the pattern of musical notes?
Law of octaves (1865)
Newlands law of octaves was true for only elements upto _____.
Calcium
What was awarded to Newlands for his work of Law of Octaves?
He was awarded
Davy Medal in 1887 by the Royal Society,
London
The Periodic Law, as we know it today owes
its development to ____ and ____.
Russian chemist, Dmitri
Mendeleev (1834-1907) and the German
chemist, Lothar Meyer (1830-1895)
Lothar Meyer
plotted the physical properties such as atomic
volume, melting point and boiling point
against atomic weight and obtained a
periodically repeated pattern. Unlike
Newlands, Lothar Meyer observed
A change in length of the repeating pattern
By the year ____ Lothar Meyer had developed a table of the elements that closely resembles the modern periodic table.
1868
Medeleeves periodic law states
The properties of the elements are a
periodic function of their atomic
weights.
The two aspects Mendeleev relied on, while making the periodic table.
•the similarities in the empirical formulas
•properties of the compounds formed by the
elements.
Site an example for Mendeleev not following his own periodic law.
iodine with lower atomic weight
than that of tellurium (Group VI) was placed
in Group VII along with fluorine, chlorine,
bromine because of similarities in properties
What is Eka Aluminum
Gallium
What is Eka Silicon
Germanium
Mendeleeves periodic table was published in the year
1905
How did Henry Moseley show that the atomic number is a more fundamental
property of an element than its atomic mass?
In 1913, the
English physicist, Henry Moseley observed
regularities in the characteristic X-ray spectra
of the elements. A plot of ν (whereν is
frequency of X-rays emitted) against atomic
number (Z ) gave a straight line and not the
plot of ν vs atomic mass.
Modern periodic law states
The physical and chemical properties
of the elements are periodic functions
of their atomic numbers.
Ore of uranium
Pitch Blende
Pitch Blende contains
Neptunium
Plutonium
Actinium
Protactinium
The Periodic Law revealed important
analogies among the ___ naturally occurring
elements
94
Assertion : A renewed interest was stimulated
in Inorganic Chemistry and
carried into the present with the creation
of artificially produced short-lived elements.
Reason :The Periodic Law revealed important
analogies among the 94 naturally occurring
elements (neptunium and plutonium like
actinium and protoactinium are also found in
pitch blende – an ore of uranium
Both A and R are correct and Reason is the correct explanation of the assertion.
Most convenient and widely used form of periodic table is
The long form of periodic table.
Horizontal rows in Mendeleeve’s periodic table is called
Series
Horizontal rows in long form of periodic table are alled
Periods
Elements having similar outer electronic configuration is arranged as
Vertical columns called groups/families.
Expand IUPAC
International Union of Pure and Applied Chemistry
How many periods and groups are there in the long form of the periodic table?
7 periods and 18 groups.
What does the period number represent?
The highest principal quantum number.
No of elements in the 7 periods?
2
8
8
18
18
32
Seventh period - Incomplete
Theoretical maximum 32
The 14 elements of sixth period is separately placed at the bottom and are called
Lanthanoids
The 14 elements of seventh period is separately placed at the bottom and are called
Actinoids
Elements after 100.
101 - Mendeleevium
102- Nobelium
103 - Lawrencium
104 - Rutherfordium
105 - Dubnium
106 - Seaborgium
107- Bohrium
108 - Hassium
109 - Meitnerium
110 -Darmstadtium
111 - Roentgenium
112 - Coppernicium
113 - Nihonium
114 - Flerovium
115 - Moscovium
116 -Livermorium
117 -Tenassine
118 -Oganesson
Temporary name of element with atomic number 103
Unt
Permanent name of 104
Rutherfordium
Permanent name represent
The country or state of country where the element was discovered
Or Pay tribute to a notable scientist.
