238628
Which of the following is not iso electronic with $\mathrm{H}_2 \mathrm{~S}$ ?
1 $\mathrm{F}_2$ gas
2 Oxide ion
3 $\mathrm{Ca}^{+2}$
4 $\mathrm{Sc}^{+3}$
Explanation:
Iso electronic species are those which have same number of electron. The total number of electron in the given species are as follows. $\begin{aligned} & \mathrm{H}_2 \mathrm{~S}=2+16=18 \text { electron } \\ & \mathrm{F}_2=9+9=18 \text { electron } \\ & \mathrm{O}^{2-}=8+2=10 \text { electron } \\ & \mathrm{Ca}^{2+}=20-218 \text { electron } \\ & \mathrm{Sc}^{3+}=21-3=18 \text { electron } \end{aligned}$ Thus $\mathrm{O}^{2-}$ (Oxide ion) is not iso-electronic with $\mathrm{H}_2 \mathrm{~S}$.
Structure of Atom
238631
The effective nuclear charge of an elements with three valence electrons is 2.60. What is the atomic number of the element?
1 1
2 2
3 3
4 4
5 5
Explanation:
: Effective nuclear charge $=2.60$ and valence shell contain 3 electrons. Thus, the minimum number of main shells for the given element are two i.e. $(x=2)$ and its configuration will be $1 \mathrm{~s}^2, 2 \mathrm{~s}^2, 2 \mathrm{p}^1$ So, that the given element has 5 electrons in all also, for a neutral atom. Therefore, no. of electrons $=$ Atomic number There, the atomic number of the element is 5 .
Kerala-CEE-2018
Structure of Atom
238632
The number of electrons, protons and neutrons in a species are equal to 10,11 and 12 respectively. The proper symbol of the species is
1 ${ }_{11}^{22} \mathrm{Na}^{+}$
2 ${ }_{11}^{23} \mathrm{Na}$
3 ${ }_{10}^{23} \mathrm{Ne}$
4 ${ }_{11}^{23} \mathrm{Na}^{+}$
5 ${ }_{11}^{23} \mathrm{Na}^{2+}$
Explanation:
No. of electron present $=$ no. of atomic no. No. of protons $=$ No. of electron $=$ atomic no. $\begin{aligned} & { }_{11}^{22} \mathrm{Na}^{+} \Rightarrow \text { No. of electron }=10 \\ & \Rightarrow \text { No. of proton }=11 \\ & \Rightarrow \text { No. of neutron }=\mathrm{A}-\mathrm{Z} \\ & =23-11 \\ & =12 \\ & \end{aligned}$
Kerala-CEE-2020
Structure of Atom
238633
$1 \mathrm{u}(\mathrm{amu})$ is equal to
1 $1.492 \times 10^{-10} \mathrm{~J}$
2 $1.492 \times 10^{-7} \mathrm{~J}$
3 $1.492 \times 10^{-13} \mathrm{~J}$
4 $6.023 \times 10^{23} \mathrm{~J}$
Explanation:
$1 \mathrm{u}$ (unified mass) is equal to exactly $1 / 12^{\text {th }}$ of the mass of $\mathrm{C}^{12}$ atom. Thus, $1 \mathrm{u}=\frac{1}{12} \times \frac{12 \mathrm{~g}}{6.022 \times 10^{23}}$ $1 \mathrm{u}=1.66 \times 10^{-24}=-1.66 \times 10^{-27} \mathrm{Kg}$ Since, $\mathrm{E}=\mathrm{mc}^2$, thus $\begin{aligned} & =1.66 \times 10^{-27} \times\left(3 \times 10^8\right) \mathrm{Kg} \mathrm{m}^2 \mathrm{~s}^2 \\ & =1.492 \times 10^{-10} \mathrm{~J} \end{aligned}$
MHT CET-2010
Structure of Atom
238641
The atomic number of an element ' $M$ ' is 26 . How many electrons are present in the M-shell of the element in its $M^{3+}$ state?
238628
Which of the following is not iso electronic with $\mathrm{H}_2 \mathrm{~S}$ ?
1 $\mathrm{F}_2$ gas
2 Oxide ion
3 $\mathrm{Ca}^{+2}$
4 $\mathrm{Sc}^{+3}$
Explanation:
Iso electronic species are those which have same number of electron. The total number of electron in the given species are as follows. $\begin{aligned} & \mathrm{H}_2 \mathrm{~S}=2+16=18 \text { electron } \\ & \mathrm{F}_2=9+9=18 \text { electron } \\ & \mathrm{O}^{2-}=8+2=10 \text { electron } \\ & \mathrm{Ca}^{2+}=20-218 \text { electron } \\ & \mathrm{Sc}^{3+}=21-3=18 \text { electron } \end{aligned}$ Thus $\mathrm{O}^{2-}$ (Oxide ion) is not iso-electronic with $\mathrm{H}_2 \mathrm{~S}$.
Structure of Atom
238631
The effective nuclear charge of an elements with three valence electrons is 2.60. What is the atomic number of the element?
1 1
2 2
3 3
4 4
5 5
Explanation:
: Effective nuclear charge $=2.60$ and valence shell contain 3 electrons. Thus, the minimum number of main shells for the given element are two i.e. $(x=2)$ and its configuration will be $1 \mathrm{~s}^2, 2 \mathrm{~s}^2, 2 \mathrm{p}^1$ So, that the given element has 5 electrons in all also, for a neutral atom. Therefore, no. of electrons $=$ Atomic number There, the atomic number of the element is 5 .
Kerala-CEE-2018
Structure of Atom
238632
The number of electrons, protons and neutrons in a species are equal to 10,11 and 12 respectively. The proper symbol of the species is
1 ${ }_{11}^{22} \mathrm{Na}^{+}$
2 ${ }_{11}^{23} \mathrm{Na}$
3 ${ }_{10}^{23} \mathrm{Ne}$
4 ${ }_{11}^{23} \mathrm{Na}^{+}$
5 ${ }_{11}^{23} \mathrm{Na}^{2+}$
Explanation:
No. of electron present $=$ no. of atomic no. No. of protons $=$ No. of electron $=$ atomic no. $\begin{aligned} & { }_{11}^{22} \mathrm{Na}^{+} \Rightarrow \text { No. of electron }=10 \\ & \Rightarrow \text { No. of proton }=11 \\ & \Rightarrow \text { No. of neutron }=\mathrm{A}-\mathrm{Z} \\ & =23-11 \\ & =12 \\ & \end{aligned}$
Kerala-CEE-2020
Structure of Atom
238633
$1 \mathrm{u}(\mathrm{amu})$ is equal to
1 $1.492 \times 10^{-10} \mathrm{~J}$
2 $1.492 \times 10^{-7} \mathrm{~J}$
3 $1.492 \times 10^{-13} \mathrm{~J}$
4 $6.023 \times 10^{23} \mathrm{~J}$
Explanation:
$1 \mathrm{u}$ (unified mass) is equal to exactly $1 / 12^{\text {th }}$ of the mass of $\mathrm{C}^{12}$ atom. Thus, $1 \mathrm{u}=\frac{1}{12} \times \frac{12 \mathrm{~g}}{6.022 \times 10^{23}}$ $1 \mathrm{u}=1.66 \times 10^{-24}=-1.66 \times 10^{-27} \mathrm{Kg}$ Since, $\mathrm{E}=\mathrm{mc}^2$, thus $\begin{aligned} & =1.66 \times 10^{-27} \times\left(3 \times 10^8\right) \mathrm{Kg} \mathrm{m}^2 \mathrm{~s}^2 \\ & =1.492 \times 10^{-10} \mathrm{~J} \end{aligned}$
MHT CET-2010
Structure of Atom
238641
The atomic number of an element ' $M$ ' is 26 . How many electrons are present in the M-shell of the element in its $M^{3+}$ state?
238628
Which of the following is not iso electronic with $\mathrm{H}_2 \mathrm{~S}$ ?
1 $\mathrm{F}_2$ gas
2 Oxide ion
3 $\mathrm{Ca}^{+2}$
4 $\mathrm{Sc}^{+3}$
Explanation:
Iso electronic species are those which have same number of electron. The total number of electron in the given species are as follows. $\begin{aligned} & \mathrm{H}_2 \mathrm{~S}=2+16=18 \text { electron } \\ & \mathrm{F}_2=9+9=18 \text { electron } \\ & \mathrm{O}^{2-}=8+2=10 \text { electron } \\ & \mathrm{Ca}^{2+}=20-218 \text { electron } \\ & \mathrm{Sc}^{3+}=21-3=18 \text { electron } \end{aligned}$ Thus $\mathrm{O}^{2-}$ (Oxide ion) is not iso-electronic with $\mathrm{H}_2 \mathrm{~S}$.
Structure of Atom
238631
The effective nuclear charge of an elements with three valence electrons is 2.60. What is the atomic number of the element?
1 1
2 2
3 3
4 4
5 5
Explanation:
: Effective nuclear charge $=2.60$ and valence shell contain 3 electrons. Thus, the minimum number of main shells for the given element are two i.e. $(x=2)$ and its configuration will be $1 \mathrm{~s}^2, 2 \mathrm{~s}^2, 2 \mathrm{p}^1$ So, that the given element has 5 electrons in all also, for a neutral atom. Therefore, no. of electrons $=$ Atomic number There, the atomic number of the element is 5 .
Kerala-CEE-2018
Structure of Atom
238632
The number of electrons, protons and neutrons in a species are equal to 10,11 and 12 respectively. The proper symbol of the species is
1 ${ }_{11}^{22} \mathrm{Na}^{+}$
2 ${ }_{11}^{23} \mathrm{Na}$
3 ${ }_{10}^{23} \mathrm{Ne}$
4 ${ }_{11}^{23} \mathrm{Na}^{+}$
5 ${ }_{11}^{23} \mathrm{Na}^{2+}$
Explanation:
No. of electron present $=$ no. of atomic no. No. of protons $=$ No. of electron $=$ atomic no. $\begin{aligned} & { }_{11}^{22} \mathrm{Na}^{+} \Rightarrow \text { No. of electron }=10 \\ & \Rightarrow \text { No. of proton }=11 \\ & \Rightarrow \text { No. of neutron }=\mathrm{A}-\mathrm{Z} \\ & =23-11 \\ & =12 \\ & \end{aligned}$
Kerala-CEE-2020
Structure of Atom
238633
$1 \mathrm{u}(\mathrm{amu})$ is equal to
1 $1.492 \times 10^{-10} \mathrm{~J}$
2 $1.492 \times 10^{-7} \mathrm{~J}$
3 $1.492 \times 10^{-13} \mathrm{~J}$
4 $6.023 \times 10^{23} \mathrm{~J}$
Explanation:
$1 \mathrm{u}$ (unified mass) is equal to exactly $1 / 12^{\text {th }}$ of the mass of $\mathrm{C}^{12}$ atom. Thus, $1 \mathrm{u}=\frac{1}{12} \times \frac{12 \mathrm{~g}}{6.022 \times 10^{23}}$ $1 \mathrm{u}=1.66 \times 10^{-24}=-1.66 \times 10^{-27} \mathrm{Kg}$ Since, $\mathrm{E}=\mathrm{mc}^2$, thus $\begin{aligned} & =1.66 \times 10^{-27} \times\left(3 \times 10^8\right) \mathrm{Kg} \mathrm{m}^2 \mathrm{~s}^2 \\ & =1.492 \times 10^{-10} \mathrm{~J} \end{aligned}$
MHT CET-2010
Structure of Atom
238641
The atomic number of an element ' $M$ ' is 26 . How many electrons are present in the M-shell of the element in its $M^{3+}$ state?
238628
Which of the following is not iso electronic with $\mathrm{H}_2 \mathrm{~S}$ ?
1 $\mathrm{F}_2$ gas
2 Oxide ion
3 $\mathrm{Ca}^{+2}$
4 $\mathrm{Sc}^{+3}$
Explanation:
Iso electronic species are those which have same number of electron. The total number of electron in the given species are as follows. $\begin{aligned} & \mathrm{H}_2 \mathrm{~S}=2+16=18 \text { electron } \\ & \mathrm{F}_2=9+9=18 \text { electron } \\ & \mathrm{O}^{2-}=8+2=10 \text { electron } \\ & \mathrm{Ca}^{2+}=20-218 \text { electron } \\ & \mathrm{Sc}^{3+}=21-3=18 \text { electron } \end{aligned}$ Thus $\mathrm{O}^{2-}$ (Oxide ion) is not iso-electronic with $\mathrm{H}_2 \mathrm{~S}$.
Structure of Atom
238631
The effective nuclear charge of an elements with three valence electrons is 2.60. What is the atomic number of the element?
1 1
2 2
3 3
4 4
5 5
Explanation:
: Effective nuclear charge $=2.60$ and valence shell contain 3 electrons. Thus, the minimum number of main shells for the given element are two i.e. $(x=2)$ and its configuration will be $1 \mathrm{~s}^2, 2 \mathrm{~s}^2, 2 \mathrm{p}^1$ So, that the given element has 5 electrons in all also, for a neutral atom. Therefore, no. of electrons $=$ Atomic number There, the atomic number of the element is 5 .
Kerala-CEE-2018
Structure of Atom
238632
The number of electrons, protons and neutrons in a species are equal to 10,11 and 12 respectively. The proper symbol of the species is
1 ${ }_{11}^{22} \mathrm{Na}^{+}$
2 ${ }_{11}^{23} \mathrm{Na}$
3 ${ }_{10}^{23} \mathrm{Ne}$
4 ${ }_{11}^{23} \mathrm{Na}^{+}$
5 ${ }_{11}^{23} \mathrm{Na}^{2+}$
Explanation:
No. of electron present $=$ no. of atomic no. No. of protons $=$ No. of electron $=$ atomic no. $\begin{aligned} & { }_{11}^{22} \mathrm{Na}^{+} \Rightarrow \text { No. of electron }=10 \\ & \Rightarrow \text { No. of proton }=11 \\ & \Rightarrow \text { No. of neutron }=\mathrm{A}-\mathrm{Z} \\ & =23-11 \\ & =12 \\ & \end{aligned}$
Kerala-CEE-2020
Structure of Atom
238633
$1 \mathrm{u}(\mathrm{amu})$ is equal to
1 $1.492 \times 10^{-10} \mathrm{~J}$
2 $1.492 \times 10^{-7} \mathrm{~J}$
3 $1.492 \times 10^{-13} \mathrm{~J}$
4 $6.023 \times 10^{23} \mathrm{~J}$
Explanation:
$1 \mathrm{u}$ (unified mass) is equal to exactly $1 / 12^{\text {th }}$ of the mass of $\mathrm{C}^{12}$ atom. Thus, $1 \mathrm{u}=\frac{1}{12} \times \frac{12 \mathrm{~g}}{6.022 \times 10^{23}}$ $1 \mathrm{u}=1.66 \times 10^{-24}=-1.66 \times 10^{-27} \mathrm{Kg}$ Since, $\mathrm{E}=\mathrm{mc}^2$, thus $\begin{aligned} & =1.66 \times 10^{-27} \times\left(3 \times 10^8\right) \mathrm{Kg} \mathrm{m}^2 \mathrm{~s}^2 \\ & =1.492 \times 10^{-10} \mathrm{~J} \end{aligned}$
MHT CET-2010
Structure of Atom
238641
The atomic number of an element ' $M$ ' is 26 . How many electrons are present in the M-shell of the element in its $M^{3+}$ state?
238628
Which of the following is not iso electronic with $\mathrm{H}_2 \mathrm{~S}$ ?
1 $\mathrm{F}_2$ gas
2 Oxide ion
3 $\mathrm{Ca}^{+2}$
4 $\mathrm{Sc}^{+3}$
Explanation:
Iso electronic species are those which have same number of electron. The total number of electron in the given species are as follows. $\begin{aligned} & \mathrm{H}_2 \mathrm{~S}=2+16=18 \text { electron } \\ & \mathrm{F}_2=9+9=18 \text { electron } \\ & \mathrm{O}^{2-}=8+2=10 \text { electron } \\ & \mathrm{Ca}^{2+}=20-218 \text { electron } \\ & \mathrm{Sc}^{3+}=21-3=18 \text { electron } \end{aligned}$ Thus $\mathrm{O}^{2-}$ (Oxide ion) is not iso-electronic with $\mathrm{H}_2 \mathrm{~S}$.
Structure of Atom
238631
The effective nuclear charge of an elements with three valence electrons is 2.60. What is the atomic number of the element?
1 1
2 2
3 3
4 4
5 5
Explanation:
: Effective nuclear charge $=2.60$ and valence shell contain 3 electrons. Thus, the minimum number of main shells for the given element are two i.e. $(x=2)$ and its configuration will be $1 \mathrm{~s}^2, 2 \mathrm{~s}^2, 2 \mathrm{p}^1$ So, that the given element has 5 electrons in all also, for a neutral atom. Therefore, no. of electrons $=$ Atomic number There, the atomic number of the element is 5 .
Kerala-CEE-2018
Structure of Atom
238632
The number of electrons, protons and neutrons in a species are equal to 10,11 and 12 respectively. The proper symbol of the species is
1 ${ }_{11}^{22} \mathrm{Na}^{+}$
2 ${ }_{11}^{23} \mathrm{Na}$
3 ${ }_{10}^{23} \mathrm{Ne}$
4 ${ }_{11}^{23} \mathrm{Na}^{+}$
5 ${ }_{11}^{23} \mathrm{Na}^{2+}$
Explanation:
No. of electron present $=$ no. of atomic no. No. of protons $=$ No. of electron $=$ atomic no. $\begin{aligned} & { }_{11}^{22} \mathrm{Na}^{+} \Rightarrow \text { No. of electron }=10 \\ & \Rightarrow \text { No. of proton }=11 \\ & \Rightarrow \text { No. of neutron }=\mathrm{A}-\mathrm{Z} \\ & =23-11 \\ & =12 \\ & \end{aligned}$
Kerala-CEE-2020
Structure of Atom
238633
$1 \mathrm{u}(\mathrm{amu})$ is equal to
1 $1.492 \times 10^{-10} \mathrm{~J}$
2 $1.492 \times 10^{-7} \mathrm{~J}$
3 $1.492 \times 10^{-13} \mathrm{~J}$
4 $6.023 \times 10^{23} \mathrm{~J}$
Explanation:
$1 \mathrm{u}$ (unified mass) is equal to exactly $1 / 12^{\text {th }}$ of the mass of $\mathrm{C}^{12}$ atom. Thus, $1 \mathrm{u}=\frac{1}{12} \times \frac{12 \mathrm{~g}}{6.022 \times 10^{23}}$ $1 \mathrm{u}=1.66 \times 10^{-24}=-1.66 \times 10^{-27} \mathrm{Kg}$ Since, $\mathrm{E}=\mathrm{mc}^2$, thus $\begin{aligned} & =1.66 \times 10^{-27} \times\left(3 \times 10^8\right) \mathrm{Kg} \mathrm{m}^2 \mathrm{~s}^2 \\ & =1.492 \times 10^{-10} \mathrm{~J} \end{aligned}$
MHT CET-2010
Structure of Atom
238641
The atomic number of an element ' $M$ ' is 26 . How many electrons are present in the M-shell of the element in its $M^{3+}$ state?
