MCQ 11 Mark
The element which forms a basis oxide has the atomic number of:
AnswerPotassium $(K)$ forms a basic oxide and has an atomic number of $19.$
The atomic numbers of $18, 17$ and $14$ correspond to acidic oxides.
View full question & answer→MCQ 21 Mark
Which of the following is the valence shell for the elements of second period of the modern periodic table?
- A
$M$ shell.
- B
$K$ shell.
- ✓
$L$ shell.
- D
$N$ shell.
AnswerCorrect option: C. $L$ shell.
$L$ is the valence shell for elements of the second period of the modern periodic table,
since the period number is decided by the number of valence shells.
View full question & answer→MCQ 31 Mark
An element which is an essential constituent of all organic compounds belongs to following group of modern periodic table.
- A
Group $4.$
- ✓
Group $14.$
- C
Group $15.$
- D
Group $16.$
AnswerCorrect option: B. Group $14.$
Carbon is the essential constituent of all organic compounds and belongs to Group $14$ of the modern periodic table.
Electronic configuration of carbon $(6):$
$\begin{matrix}\text{K}\ \ \text{L}\\2\ \ 4\end{matrix}$
Group number $=$ valence shell $+ 10$
$= 4 + 10$
$= 14.$
View full question & answer→MCQ 41 Mark
The electronic configuration of the atom of an element $X$ is $2, 8, 4$. In modern periodic table, the element $X$ is places in:
- A
$2^{nd}$ group.
- B
$4^{th}$ group.
- ✓
$14^{th}$ group.
- D
$8^{th}$ group.
AnswerCorrect option: C. $14^{th}$ group.
Group number $= 10 + 4 =14$
Hence, the element $X$ is placed in the $14^{th}$ group.
View full question & answer→MCQ 51 Mark
The three imaginary elements $X, Y$ and $Z$ represent a Dobernener's triad. If the atomic mass of element $X$ is $14$ and that of element $Y$ is $46$, then the atomic mass of element $Z$ will be:
AnswerThe atomic mass of the element $Z$ is $78.$
According to Dobereiner’s law of triads,
atomic mass of $\text{Y}=\frac{\text{X}+\text{Z}}{2}$
Substituting the atomic masses we get:
$46=\frac{14+\text{Z}}{2}$
$92=14+\text{Z}$
$\therefore \text{Z}=78.$
View full question & answer→MCQ 61 Mark
The atomic numbers of four elements $P, Q, R$ and $S$ are $6, 8, 14$ and $16$ respectively. Out of these, the element known as metalloid is:
Answer$R (Si)$ is a metalloid since its atomic number is $14$ and it has $4$ valence electrons.
View full question & answer→MCQ 71 Mark
The modern periodic table was prepared by:
AnswerThe modern periodic table of elements was prepared by Neils Bohr.
View full question & answer→MCQ 81 Mark
The correct increasing order of the atomic radii of the elements oxygen, fluorine and nitrogen is:
- A
$O, F, N.$
- B
$N, F, O.$
- C
$O, N, F.$
- ✓
$F, O, N.$
AnswerCorrect option: D. $F, O, N.$
The increasing order of the atomic radii of oxygen, fluorine and nitrogen is fluorine, oxygen and nitrogen. This is because the atomic radius decreases from left to right in a period.
View full question & answer→MCQ 91 Mark
The three elements having chemical symbols of $Si, B$ and $Ge$ are:
AnswerThe three elements having the chemical symbols $Si, B$ and $Ge$ are metalloids.
View full question & answer→MCQ 101 Mark
Which of the following statement about the modern periodic table is correct?
- A
It has $18$ horizontal rows known as periods.
- B
It has $7$ vertical columns known as periods.
- ✓
It has $18$ vertical columns known as groups.
- D
It has $7$ horizontal rows known as groups.
AnswerCorrect option: C. It has $18$ vertical columns known as groups.
In the modern periodic table, there are $18$ vertical columns known as groups.
View full question & answer→MCQ 111 Mark
The atomic number of an element is $20.$ In modern periodic table, this element is placed:
- A
$2^{nd}$ period.
- ✓
$4^{th}$ period.
- C
$3^{rd}$ period.
- D
$1^{st}$ period.
AnswerCorrect option: B. $4^{th}$ period.
Electronic configuration:
$\begin{matrix}\text{K}\ \ \text{L}\ \ \text{M}\ \ \ \text{N}\\2\ \ \ 8\ \ \ 8 \ \ \ \ 2\end{matrix} $
Hence, from the electronic configuration, it is clear that the outermost electron goes into the $4^{th}$ shell. So, the element would be placed in the $4^{th}$ period.
View full question & answer→MCQ 121 Mark
Where would you locate the element with electronic configuration $2, 8$ in the modern periodic table?
- A
Group $8.$
- B
Group $2.$
- ✓
Group $18.$
- D
Group $10.$
AnswerCorrect option: C. Group $18.$
The element with an electronic configuration of $(2, 8)$ belongs to group $18 ($noble or inert gases$)$ of the periodic table, as the elements in this group have their valence shell completely filled with electrons.
Group number $=$ valence shell $+ 10$
$= 8 + 10 = 18.$
View full question & answer→MCQ 131 Mark
The Newland's law of octaves for the classification of elements was not found to be applicable only up to the element:
AnswerThe Newlands' law of octaves for the classification of elements was applicable only up to the element calcium.
View full question & answer→MCQ 141 Mark
The atomic numbers of the elements $Na, Mg, K$ and $Ca$ are $11, 12, 19$ and $20$ respectively. The element having the largest atomic radius is:
AnswerPotassium $(K)$ with an atomic number of $19$ has the largest atomic radius.
This is because sodium and potassium are elements of group $1.$
On moving from top to bottom in a group, the atomic radius increases.
Magnesium and calcium are elements of group $2.$
The size of the atomic radius decreases on moving from left to right in a period of the periodic table.
View full question & answer→MCQ 151 Mark
The element which can from an acidic oxide should be the one whose atomic number is:
AnswerThe element which can form an acidic oxide should be the one with atomic number $16.$
Sulphur has an atomic number of $16$ and sulphur oxide is acidic.
View full question & answer→MCQ 161 Mark
The elements $A, B, C$ and $D$ belong to groups $1, 2, 14$ and $17$ respectively of the periodic table. Which of the following pairs of elements would produce a covalent bond?
- A
$A$ and $D.$
- ✓
$C$ and $D.$
- C
$A$ and $B.$
- D
$B$ and $C.$
AnswerCorrect option: B. $C$ and $D.$
$C$ and $D.$
View full question & answer→MCQ 171 Mark
Which of the following statement is correct in regard to the classification of elements?
- A
Elements in modern periodic table are arranged on the basis of increasing atomic masses.
- B
Elements in Mendeleev's periodic table are arranged on the basis of increasing atomic numbers.
- C
In modern periodic table, the element nickel of lower atomic mass is kept before the element cobalt of higher atomic mass.
- ✓
In modern periodic table, the isotopes of chlorine having different atomic masses are kept in the same group.
AnswerCorrect option: D. In modern periodic table, the isotopes of chlorine having different atomic masses are kept in the same group.
The isotopes of chlorine, having different atomic masses but same atomic numbers are kept in the same group in the modern periodic table.
View full question & answer→MCQ 181 Mark
Which of the following are the correct characteristics of isotopes of an element?
$(i).$ Same atomic mass.
$(ii).$ Same atomic number.
$(iii).$ Same physical properties.
$(iv).$ Same chemical properties.
AnswerCorrect option: D. $(ii)$ and $(iv).$
Isotopes of an element have the same atomic number and the same chemical properties.
View full question & answer→MCQ 191 Mark
Which of the following set of elements is written correctly in the order of their increasing metallic character?
- A
$\ce{Mg, Al, Si}.$
- B
$\ce{C, O, N}.$
- C
$\ce{Na, Li, K}.$
- ✓
$\ce{Be, Mg, Ca}.$
AnswerCorrect option: D. $\ce{Be, Mg, Ca}.$
$\ce{Be, Mg}$ and $\ce{Ca}$ are elements of group $2,$ written in order of their increasing metallic character. On moving down in the group, the metallic character increases.
View full question & answer→MCQ 201 Mark
Which of the following element does not lose an electron easily?
Answer$F$ is the element that does not lose an electron easily, as it is a non $-$ metal $($halogen$)$ belonging to group $17$ of the periodic table.
View full question & answer→MCQ 211 Mark
The elements $\ce{A, B, C, D}$ and $E$ have atomic numbers $9, 11, 17, 12$ and $13$ respectively. The pair of elements which belongs to the same group of the periodic table is:
- A
$A$ and $B.$
- B
$B$ and $D.$
- ✓
$A$ and $C.$
- D
$D$ and $E.$
AnswerCorrect option: C. $A$ and $C.$
Electronic configuration of $A (9):$
$\begin{matrix}\text{K} \ \ \text{L}\\2\ \ \ 7\end{matrix}$
Electronic configuration of $C (17):$
$\begin{matrix}\text{K}\ \ \text{L}\ \ \text{M}\\2\ \ \ 8\ \ \ 7\end{matrix}$
Group number of $A$ and $B =$ valence electron $+ 10$
$= 7 + 10 $
$= 17.$
View full question & answer→MCQ 221 Mark
An element $X$ forms an oxide $\ce{X_2O_3}$. In which group of Mendeleev's periodic table is this element placed?
- A
Group $II.$
- ✓
Group $III.$
- C
Group $V.$
- D
Group $VIII.$
AnswerCorrect option: B. Group $III.$
The element which forms the oxide $\ce{X_2O_3}$ is placed in group $3$ of the periodic table.
View full question & answer→MCQ 231 Mark
In Mendeleev's periodic table, gaps were left for the elements to be discovered later on. An element which found a vacant place in the periodic table later on is:
AnswerGermanium $($eka $-$ silicon$)$ is the element which found a vacant place in the periodic table later on.
View full question & answer→MCQ 241 Mark
Which of the following element would lose an electron easily?
MCQ 251 Mark
Which one of the following does not increase while moving down the group of the periodic table?
AnswerThe number of valence electrons does not increase while moving down the group in the periodic table.
View full question & answer→MCQ 261 Mark
On moving from left to right in a period of the periodic table, the atomic number of elements increases. What happens to the size of atoms of elements on moving from left to right in a period?
- A
- ✓
- C
- D
First increases then decreases.
AnswerThe size of the atom decreases on moving from left to right in a period of the periodic table. With an increment in the atomic number, both the proton number and the nuclear positive charge increase. As the nucleus attracts the outermost electron, the size of the atom decreases.
View full question & answer→MCQ 271 Mark
Which of the following statements is not a correct statements about the trends when going from left to right across the periods of the periodic table?
- A
The elements become less metallic in nature.
- B
The number of valence electrons increases.
- ✓
The atoms lose their electrons more easily.
- D
The oxides become more acidic.
AnswerCorrect option: C. The atoms lose their electrons more easily.
On moving from left to right in the periodic table, the tendency of an atom to lose electrons decreases.
View full question & answer→MCQ 281 Mark
The correct formula of the oxide of Eka$-$aluminium element predicted by Mendeleev was:
- A
$\ce{EaO_3.}$
- B
$\ce{Ea_3O_2.}$
- ✓
$\ce{Ea_2O_3.}$
- D
$\ce{EaO.}$
AnswerCorrect option: C. $\ce{Ea_2O_3.}$
The correct formula for the oxide of eka $-$ aluminium, as predicted by Mendeleev, is $\ce{Ea_2O_3.}$
View full question & answer→MCQ 291 Mark
The atomic particle whose number in the atoms of an element always remains the same and which forms the real basis for the modern classification of elements is:
MCQ 301 Mark
In Mendeleev's periodic table, gap was not left for one of the following elements. This element is:
AnswerIn Mendeleev's periodic table, a gap was left for gallium, scandium and germanium.
View full question & answer→MCQ 311 Mark
According to Mendeleev's periodic law, the elements were arranged in the periodic table in the order of:
- A
Decreasing atomic numbers.
- B
Increasing atomic numbers.
- C
Decreasing atomic masses.
- ✓
Increasing atomic masses.
AnswerCorrect option: D. Increasing atomic masses.
According to Mendeleev's periodic law, the elements in the periodic table were arranged in the order of increasing atomic masses.
View full question & answer→MCQ 321 Mark
Five elements $\ce{A, B, C, D}$ and $\ce{E}$ have atomic numbers of $2, 3, 7, 10$ and $18$ respectively. The elements which belong to the same period of the periodic table are:
- A
$\ce{A, B, C}.$
- ✓
$\ce{B, C, D}.$
- C
$\ce{A, D, E}.$
- D
$\ce{B, D, E}.$
AnswerCorrect option: B. $\ce{B, C, D}.$
$B, C$ and $D,$ with atomic numbers $3, 7$ and $10$ respectively, belong to the same period of the periodic table. This is because the elements $B, C$ and $D$ have the same valence shell $(L$ shell$).$
View full question & answer→MCQ 331 Mark
The element which has the maximum number of valence electrons is:
AnswerPhosphorus $(P)$ has the maximum number of valence electrons, equal to $5.$
Electronic configuration of $P (15):$
$\begin{matrix}\text{K}\ \ \text{L}\ \ \text{M}\\2\ \ \ 8\ \ \ 5\end{matrix}$
Sodium $(Na)$ has $1,$ Silicon has $4$ and Aluminium $(Al)$ has $3.$
View full question & answer→