1. Among chemical properties, Mendeléev concentrated on the compounds formed by elements with oxygen and hydrogen. 2. He selected hydrogen and oxygen as they are very reactive and formed compounds with most elements. 3. The formulae of the hydrides and oxides formed by an element were treated as oneRead more
1. Among chemical properties, Mendeléev concentrated on the compounds formed by elements with
oxygen and hydrogen.
2. He selected hydrogen and oxygen as they are very reactive and formed compounds with most elements.
3. The formulae of the hydrides and oxides formed by an element were treated as one of the basic properties of an element for its classification.
4. He then took 63 cards and on each card he wrote down the properties of one element.
1. It was found that the Law of Octaves was applicable only upto calcium, as after calcium every eighth element did not possess properties similar to that of the first. 2. Now we know more than 56 elements, but in Newland's table only 56 elements can be placed,
1. It was found that the Law of Octaves was applicable only upto calcium, as after calcium every eighth element did not possess properties similar to that of the first.
2. Now we know more than 56 elements, but in Newland’s table only 56 elements can be placed,
How could the Modern Periodic Table remove various anomalies of Mendeléev’s Periodic Table?
Proper place for inert gases. Now elements are arranged according to atomic number instead of atomic mass. Isotopes problems is solved.
- Proper place for inert gases.
- Now elements are arranged according to atomic number instead of atomic mass.
- Isotopes problems is solved.
See lessName the elements that separated the metals and non-metals in periodic table.
Metalloids
Metalloids
See lessAn element ‘x’ belongs to groups 2. Find its valency.
All the elements of group 2 have valency 2.
All the elements of group 2 have valency 2.
See lessFill in the blanks: According to Newland’s law of octave ______________is similar to oxygen.
S, Fe and Se
S, Fe and Se
See lessFill in the blanks: The basis of modern Periodic table is _______________
It is based on periodicity of atomic number of elements.
It is based on periodicity of atomic number of elements.
See lessWhy do you think the noble gases are placed in a separate group?
Because in Noble gases the outer most shell is always filled completely.
Because in Noble gases the outer most shell is always filled completely.
See lessWhat were the criteria used by Mendeleev in creating his Periodic Table?
1. Among chemical properties, Mendeléev concentrated on the compounds formed by elements with oxygen and hydrogen. 2. He selected hydrogen and oxygen as they are very reactive and formed compounds with most elements. 3. The formulae of the hydrides and oxides formed by an element were treated as oneRead more
1. Among chemical properties, Mendeléev concentrated on the compounds formed by elements with
See lessoxygen and hydrogen.
2. He selected hydrogen and oxygen as they are very reactive and formed compounds with most elements.
3. The formulae of the hydrides and oxides formed by an element were treated as one of the basic properties of an element for its classification.
4. He then took 63 cards and on each card he wrote down the properties of one element.
Besides gallium, which other elements have since been discovered that were left by Mendeleev in his Periodic Table? (any two)
Eka–boron as Scandium Eka–silicon as Germanium
Eka–boron as Scandium
See lessEka–silicon as Germanium
Use Mendeleev’s Periodic Table to predict the formulae for the oxides of the following elements: K, C, AI, Si, Ba.
Al is in group 3. O is in group 16 Therefore, the oxide will be Al₂O₃.
Al is in group 3.
See lessO is in group 16
Therefore, the oxide will be Al₂O₃.
What were the limitations of Newlands’ Law of Octaves?
1. It was found that the Law of Octaves was applicable only upto calcium, as after calcium every eighth element did not possess properties similar to that of the first. 2. Now we know more than 56 elements, but in Newland's table only 56 elements can be placed,
1. It was found that the Law of Octaves was applicable only upto calcium, as after calcium every eighth element did not possess properties similar to that of the first.
See less2. Now we know more than 56 elements, but in Newland’s table only 56 elements can be placed,