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what are the merits and demerits of modern periodic table.
discuss the position of hydrogen in modern periodic table?
state the modern periodic law.What is the modern periodic table called?
Give any 5 advantages and limitations of Mendeleev's periodic table and explain each of them?
Merits and dimerits of Mendeleev's periodic table.
What were the drawbacks of Mendeleev's Periodic Table?
what are the limitations of mendeleevs periodic table
WHAT ARE THE ACHIEVEMENTS OF MENDELEEVS PERIODIC TABLE?
Why Hydrogen can be placed in either group1 or group 17 in the modern periodic table?
what happens wen ethanol is heated at 443K with con H2SO4 .
What is penultimate shells and antipenultimate shells?
Find the valency of Iron by electronic configuration
What were the limitations of Dobereiner's classification?
DRAWBACKS OF DOBEREINER LAW OF TRIADS
DRAWBACKS OF NEWLANDS LAW OF OCTAVE
DRAWBACKS OF MENDELLEVS PERIODIC TABLE
how does the electronic configuration of an element relate to its position in moden periodic table ?explain with an example
plz answer..................
define valency
what are the advantages of newland's law of octaves?
which is more reactive ? calcium or magnesium ?
What is Isolated atom??
Is there any trick to learn the atomic numbers of all elements??
compare and contrast Modern periodic table and Mendeleev's periodic table .
what are the limitations of newlands law of octaves
what are the advantages of MODERN PERIODIC TABLE ?
which type of question comes in entrance exam of dps(class x going class xi)
Which element has
(a) two shells, both of which are completely filled with electrons?
(b) the electronic configuration 2, 8, 2?
(c) a total of three shells, with four electrons in its valence shell?
(d) a total of two shells, with three electrons in its valence shell?
(e) twice as many electrons in its second shell as in its first shell?
Why fluorine is more reactive than chlorine?
PERIODIC CLASSIFICATION OF ELEMENTS• Elements are classified on the basis of similarities in their properties.• Döbereiner grouped the elements into triads and Newlands gave the Law of Octaves.• Mendeléev arranged the elements in increasing order of their atomic masses and according to their chemical properties.• Mendeléev even predicted the existence of some yet to be discovered elements on the basis of gaps in his Periodic Table.• Anomalies in arrangement of elements based on increasing atomic mass could be removed when the elements were arranged in order of increasing atomic number, a fundamental property of the element discovered by Moseley.• Elements in the Modern Periodic Table are arranged in 18 vertical columns called groups and 7 horizontal rows called periods.• Elements thus arranged show periodicity of properties including atomic size, valency or combining capacity and metallic and non-metallic character.Periodic Law:‘Properties of elements are a periodic function of their atomic number.’Atomic number gives us the number of protons in the nucleus of an atom and this number increases by one in going from one element to the next. Elements, when arranged in order of increasing atomic number Z, lead us to the classification known as the Modern Periodic Table. Prediction of properties of elements could be made with more precision when elements were arranged on the basis of increasing atomic number.Position of Elements in the Modern Periodic Table :The Modern Periodic Table has 18 vertical columns known as ‘groups’ and 7 horizontal rows known as ‘periods’. Let us see what decides the placing of an element in a certain group and period. All elements of a group contain same number of valence electrons, which justifies similar chemical properties.The atomic radius decreases in moving from left to right along a period. This is due to an increase in nuclear charge which tends to pull the electrons closer to the nucleus and reduces the size of the atom.Atoms of different elements with the same number of occupied shells are placed in the same period. Na, Mg, Al, Si, P, S, Cl and Ar belong to the third period of the Modern Periodic Table, since the electrons in the atoms of these elements are filled in K, L and M shells.Metallic & Non-metallic Properties:Metals like Na and Mg are towards the left-hand side of the Periodic Table while the non-metals like sulphur and chlorine are found on the right-hand side. In the middle, we have silicon, which is classified as a semi-metal or metalloid because it exhibits some properties of both metals and non-metals.In the Modern Periodic Table, a zig-zag line separates metals from non-metals. The borderline elements – boron, silicon, germanium, arsenic, antimony, tellurium and polonium – are intermediate in properties and are called metalloids or semi-metals. Metals tend to lose electrons while forming bonds, that is, they are electropositive in nature.As the effective nuclear charge acting on the valence shell electrons increases across a period, the tendency to lose electrons will decrease. Down the group, the effective nuclear charge experienced by valence electrons is decreasing because the outermost electrons are farther away from the nucleus. Therefore, these can be lost easily. Hence metallic character decreases across a period and increases down a group.As the trends in the electronegativity show, non-metals are found on the right-hand side of the Periodic Table towards the top. These trends also help us to predict the nature of oxides formed by the elements because it is know that the oxides of metals are basic and that of non-metals are acidic in general.
• Elements are classified on the basis of similarities in their properties.
• Döbereiner grouped the elements into triads and Newlands gave the Law of Octaves.
• Mendeléev arranged the elements in increasing order of their atomic masses and according to their chemical properties.
• Mendeléev even predicted the existence of some yet to be discovered elements on the basis of gaps in his Periodic Table.
• Anomalies in arrangement of elements based on increasing atomic mass could be removed when the elements were arranged in order of increasing atomic number, a fundamental property of the element discovered by Moseley.
• Elements in the Modern Periodic Table are arranged in 18 vertical columns called groups and 7 horizontal rows called periods.
• Elements thus arranged show periodicity of properties including atomic size, valency or combining capacity and metallic and non-metallic character.
Periodic Law:‘Properties of elements are a periodic function of their atomic number.’
Atomic number gives us the number of protons in the nucleus of an atom and this number increases by one in going from one element to the next. Elements, when arranged in order of increasing atomic number Z, lead us to the classification known as the Modern Periodic Table. Prediction of properties of elements could be made with more precision when elements were arranged on the basis of increasing atomic number.
Position of Elements in the Modern Periodic Table :
The Modern Periodic Table has 18 vertical columns known as ‘groups’ and 7 horizontal rows known as ‘periods’. Let us see what decides the placing of an element in a certain group and period. All elements of a group contain same number of valence electrons, which justifies similar chemical properties.
The atomic radius decreases in moving from left to right along a period. This is due to an increase in nuclear charge which tends to pull the electrons closer to the nucleus and reduces the size of the atom.
Atoms of different elements with the same number of occupied shells are placed in the same period. Na, Mg, Al, Si, P, S, Cl and Ar belong to the third period of the Modern Periodic Table, since the electrons in the atoms of these elements are filled in K, L and M shells.
Metallic & Non-metallic Properties:
Metals like Na and Mg are towards the left-hand side of the Periodic Table while the non-metals like sulphur and chlorine are found on the right-hand side. In the middle, we have silicon, which is classified as a semi-metal or metalloid because it exhibits some properties of both metals and non-metals.
In the Modern Periodic Table, a zig-zag line separates metals from non-metals. The borderline elements – boron, silicon, germanium, arsenic, antimony, tellurium and polonium – are intermediate in properties and are called metalloids or semi-metals. Metals tend to lose electrons while forming bonds, that is, they are electropositive in nature.
As the effective nuclear charge acting on the valence shell electrons increases across a period, the tendency to lose electrons will decrease. Down the group, the effective nuclear charge experienced by valence electrons is decreasing because the outermost electrons are farther away from the nucleus. Therefore, these can be lost easily. Hence metallic character decreases across a period and increases down a group.
As the trends in the electronegativity show, non-metals are found on the right-hand side of the Periodic Table towards the top. These trends also help us to predict the nature of oxides formed by the elements because it is know that the oxides of metals are basic and that of non-metals are acidic in general.
what are the trends in modern periodic table explain briefly.
write the electronic configuration of first 20 elements of modern periodic table.
What were the criteria used by Mendeleev in creating his his periodic table?
Q.1. An element X (2,8,2) combines separately with NO3 and (SO4)2 -, (PO4)3 - radicals.
State Mendeleev's periodic law?
what is inter-electronic repulsion ?
Why do all the elements of the (a) same group have similar properties, (b) same period have different properties? answer soon
drawback of modern periodic table
Give Limitations of Mendeleevs Classification.
how does valency vary in a period on going from left to right in modern periodic table?
atomic weights of first 30 elements
which is the most reactive metal and non-metal ? and why ??
Give 2 advantages and disadvantages of Dobernier's triads.
(a) What is meant by periodicity in properties of elements with reference to the periodic table?
(b) Why do all the tendency to gain electrons change as we go from left to right across a period? Why?
among oxygen O2- ion and magnesium Mg2+ ion what has larger sizes and why???????????????
why in the 3rd period there is 8 elements and not 18th elements ? .. Give reason ..
Nitrogen (atomic number 7) and phosphorus (atomic number 15) belong to group 15 of the Periodic Table. Write the electronic configuration of these two elements. Which of these will be more electronegative? Why?
Which is more reactive sodium or lithium.why?
Name two elements you would expect to show chemical reactions similar to magnesium. What is the basis for your choice?
AN ELEMENT X HAS MASS NO.' 35 N NUMBER OF NEUTRONS 18.
1.ATOMIC NO. OF X?
PLSS EXPLAIN?
define periodicity and give its cause?
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Syllabus
what are the merits and demerits of modern periodic table.
discuss the position of hydrogen in modern periodic table?
state the modern periodic law.What is the modern periodic table called?
rnGive any 5 advantages and limitations of Mendeleev's periodic table and explain each of them?
Merits and dimerits of Mendeleev's periodic table.
What were the drawbacks of Mendeleev's Periodic Table?
what are the limitations of mendeleevs periodic table
WHAT ARE THE ACHIEVEMENTS OF MENDELEEVS PERIODIC TABLE?
Why Hydrogen can be placed in either group1 or group 17 in the modern periodic table?
what happens wen ethanol is heated at 443K with con H2SO4 .
What is penultimate shells and antipenultimate shells?
Find the valency of Iron by electronic configuration
What were the limitations of Dobereiner's classification?
DRAWBACKS OF DOBEREINER LAW OF TRIADS
DRAWBACKS OF NEWLANDS LAW OF OCTAVE
DRAWBACKS OF MENDELLEVS PERIODIC TABLE
how does the electronic configuration of an element relate to its position in moden periodic table ?explain with an example
plz answer..................
define valency
what are the advantages of newland's law of octaves?
which is more reactive ? calcium or magnesium ?
What is Isolated atom??
Is there any trick to learn the atomic numbers of all elements??
a) Determine the number of valence electrons and the valency of 'X'
b) Molecular formula of the compound when 'X' reacts with hydrogen and write it's electron dot structure
c) Name the element 'X' and state whether it is metallic or non- metallic
compare and contrast Modern periodic table and Mendeleev's periodic table .
what are the limitations of newlands law of octaves
what are the advantages of MODERN PERIODIC TABLE ?
which type of question comes in entrance exam of dps(class x going class xi)
Which element has
(a) two shells, both of which are completely filled with electrons?
(b) the electronic configuration 2, 8, 2?
(c) a total of three shells, with four electrons in its valence shell?
(d) a total of two shells, with three electrons in its valence shell?
(e) twice as many electrons in its second shell as in its first shell?
Why fluorine is more reactive than chlorine?
PERIODIC CLASSIFICATION OF ELEMENTS
• Elements are classified on the basis of similarities in their properties.
• Döbereiner grouped the elements into triads and Newlands gave the Law of Octaves.
• Mendeléev arranged the elements in increasing order of their atomic masses and according to their chemical properties.
• Mendeléev even predicted the existence of some yet to be discovered elements on the basis of gaps in his Periodic Table.
• Anomalies in arrangement of elements based on increasing atomic mass could be removed when the elements were arranged in order of increasing atomic number, a fundamental property of the element discovered by Moseley.
• Elements in the Modern Periodic Table are arranged in 18 vertical columns called groups and 7 horizontal rows called periods.
• Elements thus arranged show periodicity of properties including atomic size, valency or combining capacity and metallic and non-metallic character.
Periodic Law:‘Properties of elements are a periodic function of their atomic number.’
Atomic number gives us the number of protons in the nucleus of an atom and this number increases by one in going from one element to the next. Elements, when arranged in order of increasing atomic number Z, lead us to the classification known as the Modern Periodic Table. Prediction of properties of elements could be made with more precision when elements were arranged on the basis of increasing atomic number.
Position of Elements in the Modern Periodic Table :
The Modern Periodic Table has 18 vertical columns known as ‘groups’ and 7 horizontal rows known as ‘periods’. Let us see what decides the placing of an element in a certain group and period. All elements of a group contain same number of valence electrons, which justifies similar chemical properties.
The atomic radius decreases in moving from left to right along a period. This is due to an increase in nuclear charge which tends to pull the electrons closer to the nucleus and reduces the size of the atom.
Atoms of different elements with the same number of occupied shells are placed in the same period. Na, Mg, Al, Si, P, S, Cl and Ar belong to the third period of the Modern Periodic Table, since the electrons in the atoms of these elements are filled in K, L and M shells.
Metallic & Non-metallic Properties:
Metals like Na and Mg are towards the left-hand side of the Periodic Table while the non-metals like sulphur and chlorine are found on the right-hand side. In the middle, we have silicon, which is classified as a semi-metal or metalloid because it exhibits some properties of both metals and non-metals.
In the Modern Periodic Table, a zig-zag line separates metals from non-metals. The borderline elements – boron, silicon, germanium, arsenic, antimony, tellurium and polonium – are intermediate in properties and are called metalloids or semi-metals. Metals tend to lose electrons while forming bonds, that is, they are electropositive in nature.
As the effective nuclear charge acting on the valence shell electrons increases across a period, the tendency to lose electrons will decrease. Down the group, the effective nuclear charge experienced by valence electrons is decreasing because the outermost electrons are farther away from the nucleus. Therefore, these can be lost easily. Hence metallic character decreases across a period and increases down a group.
As the trends in the electronegativity show, non-metals are found on the right-hand side of the Periodic Table towards the top. These trends also help us to predict the nature of oxides formed by the elements because it is know that the oxides of metals are basic and that of non-metals are acidic in general.
what are the trends in modern periodic table explain briefly.
write the electronic configuration of first 20 elements of modern periodic table.
What were the criteria used by Mendeleev in creating his his periodic table?
Q.1. An element X (2,8,2) combines separately with NO3 and (SO4)2 -, (PO4)3 - radicals.
State Mendeleev's periodic law?
what is inter-electronic repulsion ?
Why do all the elements of the (a) same group have similar properties, (b) same period have different properties? answer soon
drawback of modern periodic table
Give Limitations of Mendeleevs Classification.
how does valency vary in a period on going from left to right in modern periodic table?
atomic weights of first 30 elements
which is the most reactive metal and non-metal ? and why ??
Give 2 advantages and disadvantages of Dobernier's triads.
(a) What is meant by periodicity in properties of elements with reference to the periodic table?
(b) Why do all the tendency to gain electrons change as we go from left to right across a period? Why?
among oxygen O2- ion and magnesium Mg2+ ion what has larger sizes and why???????????????
why in the 3rd period there is 8 elements and not 18th elements ? .. Give reason ..
Nitrogen (atomic number 7) and phosphorus (atomic number 15) belong to group 15 of the Periodic Table. Write the electronic configuration of these two elements. Which of these will be more electronegative? Why?
Which is more reactive sodium or lithium.why?
Name two elements you would expect to show chemical reactions similar to magnesium. What is the basis for your choice?
AN ELEMENT X HAS MASS NO.' 35 N NUMBER OF NEUTRONS 18.
1.ATOMIC NO. OF X?
PLSS EXPLAIN?
define periodicity and give its cause?