Compare and contrast the arrangement of elements in Mendeléev’s Periodic Table and the Modern Periodic Table.
Compare and contrast the arrangement of elements in Mendeléev’s Periodic Table and the Modern Periodic Table.
| Mendeleev's periodic table | Modern periodic table | ||
| $1.$ | Elements are arranged in the increasing order of their atomic masses. | $1.$ | Elements are arranged in the increasing order of their atomic numbers. |
| $2.$ | There are a total of $7$ groups (columns) and $6$ periods (rows). | $2.$ | There are a total of $18$ groups (columns) and $7$ periods (rows). |
| $3.$ | Elements having similar properties were placed directly under one another. |
$3.$ | Elements having the same valence shell are present in the same period while elements having the same number of valence electrons are present in the same group. |
| $4.$ | The position of hydrogen could not be explained. | $4.$ | Hydrogen is placed above alkali metals. |
| $5.$ | No distinguishing positions for metals and non-metals. | $5.$ | Metals are present at the left hand side of the periodic table whereas non-metals are present at the right hand side. |
Similar Questions
An atom has electronic configuration $2$, $8$, $7$.
$(a)$ What is the atomic number of this element ?
$(b)$ To which of the following elements would it be chemically similar ?(Atomic numbers are given in parentheses.)
$N(7)$ $F(9)$ $P(15)$ $Ar(18)$
An atom has electronic configuration $2$, $8$, $7$.
$(a)$ What is the atomic number of this element ?
$(b)$ To which of the following elements would it be chemically similar ?(Atomic numbers are given in parentheses.)
$N(7)$ $F(9)$ $P(15)$ $Ar(18)$
Lithium, sodium, potassium are all metals that react with water to liberate hydrogen gas. Is there any similarity in the atoms of these elements ?
Lithium, sodium, potassium are all metals that react with water to liberate hydrogen gas. Is there any similarity in the atoms of these elements ?
The position of three elements $A$, $B$ and $C$ in the Periodic Table are shown below
Group $16$
Group $17$
-
-
-
$A$
-
-
$B$
$C$
$ (a)$ State whether $A$ is a metal or non-metal.
$(b)$ State whether $C$ is more reactive or less reactive than $A$.
The position of three elements $A$, $B$ and $C$ in the Periodic Table are shown below
| Group $16$ | Group $17$ |
| - | - |
| - | $A$ |
| - | - |
| $B$ | $C$ |
$ (a)$ State whether $A$ is a metal or non-metal.
$(b)$ State whether $C$ is more reactive or less reactive than $A$.
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?
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?
By considering their position in the Periodic Table, which one of the following elements would you expect to have maximum metallic characteristic ?
$Ga$ $Ge$ $As$ $Se$ $Be$
By considering their position in the Periodic Table, which one of the following elements would you expect to have maximum metallic characteristic ?
$Ga$ $Ge$ $As$ $Se$ $Be$