Dead burnt plaster is
- $CaSO_{4}$
- $CaSO_{4} . \frac{1}{2} H_2O$
- $CaSO_{4} . H_2O$
- $CaSO_{4} . 2 H_2O$
The Correct Option is A
Solution and Explanation
Top Questions on GROUP 1 ELEMENTS
- Thermal stability order of Group 1 hydroxides is:
- MHT CET - 2025
- Chemistry
- GROUP 1 ELEMENTS
- Alkali metal with highest first ionization enthalpy is:
- KEAM - 2025
- Chemistry
- GROUP 1 ELEMENTS
- Given below are two statements: one is labelled as Assertion A and the other is labelled as Reason R:
Assertion A: Metallic sodium dissolved in liquid ammonia giving a deep blue solution which is paramagnetic.
Reasons R: The deep blue solution to the formation of amide.
In the light of the above statements, the correct answer from the options below:- NEET (UG) - 2023
- Chemistry
- GROUP 1 ELEMENTS
- The compound which does not exist.
- JEE Main - 2023
- Chemistry
- GROUP 1 ELEMENTS
Ion having highest hydration enthalpy among the given alkaline earth metal ions is:
- JEE Main - 2023
- Chemistry
- GROUP 1 ELEMENTS
Questions Asked in KCET exam
- If the number of terms in the binomial expansion of \((2x + 3)^n\) is 22, then the value of \(n\) is:
- KCET - 2025
- Binomial theorem
- Which of the following statements is/are true about equilibrium?
- KCET - 2025
- Equilibrium
A block of certain mass is placed on a rough floor. The coefficients of static and kinetic friction between the block and the floor are 0.4 and 0.25 respectively. A constant horizontal force \( F = 20 \, \text{N} \) acts on it so that the velocity of the block varies with time according to the following graph. The mass of the block is nearly (Take \( g = 10 \, \text{m/s}^2 \)):
- KCET - 2025
- work, energy and power
- A random experiment has five outcomes \(w_1, w_2, w_3, w_4, w_5\). The probabilities of the occurrence of the outcomes \(w_1, w_2, w_4, w_5\) are respectively \( \frac{1}{6}, a, b, \frac{1}{12} \) such that \(12a + 12b - 1 = 0\). Then the probabilities of occurrence of the outcome \(w_3\) is:
- KCET - 2025
- Probability
A wooden block of mass M lies on a rough floor. Another wooden block of the same mass is hanging from the point O through strings as shown in the figure. To achieve equilibrium, the coefficient of static friction between the block on the floor and the floor itself is
- KCET - 2025
- Newtons Laws of Motion
KCET Notification
Concepts Used:
Group 1 Elements
Group one of alkali metals is s-block elements with just one electron in their s-orbital. They are are alkali metals. They are named so because of the alkaline nature of the hydroxides and oxides.
Alkali metals are characterized by one s-electron in the valence shell of their atoms.
Alkali metals have a corresponding [Noble gas] ns1 electronic configuration. They occupy the first column of the periodic table. Alkali elements are:
- Lithium(Li)
- Sodium(Na)
- Potassium (K)
- Rubidium (Ru)
- Cesium (Cs)
- Francium (Fr)
They have occupied successive periods from first to seven. Francium is a radioactive element with very low half-life.
Electronic Configuration:
- Alkali metals have one electron in their valence shell.
- The electronic configuration is given by ns1. For example, the electronic configuration of lithium is given by 1ns1 2ns1.
- They tend to lose the outer shell electron to form cations with charge +1 (monovalent ions).
This makes them the most electropositive elements and due to the same reason, they are not found in the pure state.