Answer:
16
Explanation:
Group two elements are alkaline earth metal.
All these have two valance electrons. In order to achieve noble gas configuration it loses its two valance and get complete octet.
Reaction with group 16.
Reaction with oxygen,
They react with oxygen and form oxide.
2Ba + O₂ → 2BaO
2Mg + O₂ → 2MgO
2Ca + O₂ → 2CaO
this oxide form hydroxide when react with water,
BaO + H₂O → Ba(OH)₂
MgO + H₂O → Mg(OH)₂
CaO + H₂O → Ca(OH)₂
With sulfur,
Mg + S → MgS
Ca + S → CaS
Ba + S → BaS
Answer:
λ = 2.8 m
Explanation:
Given data:
Frequency of radio wave = 106.7 ×10⁶ Hz
Wavelength of radio wave = ?
Solution:
Formula:
Speed of wave = frequency × wavelength
speed of wave = 3×10⁸ m/s
by putting values,
3×10⁸ m/s = 106.7 ×10⁶ Hz × λ
Hz = s⁻¹
λ = 3×10⁸ m/s / 106.7 ×10⁶ Hz
λ = 3×10⁸ m/s / 106.7 ×10⁶ s⁻¹
λ = 0.028×10² m
λ = 2.8 m
The answer is C which is PbSo
Here we have to choose the right option which tells the moles of CaCl₂ will react with 6.2 moles of AgNO₃ in the reaction
2AgNO₃ + CaCl₂→ 2AgCl + Ca(NO₃)₂
6.2 moles of silver nitrate (AgNO₃) will react with B. 3.1 moles of calcium chloride (CaCl₂).
From the reaction: 2AgNO₃ + CaCl₂→ 2AgCl + Ca(NO₃)₂
Thus 2 moles of AgNO₃ reacts with 1 mole of CaCl₂
Henceforth, 6.2 moles of AgNO₃ reacts with 
= 3.1 moles of CaCl₂.
1 mole of CaCl₂ reacts with 2 moles of AgNO₃. Thus-
A. 2.2 moles of CaCl₂ will react with 2.2×2 = 4.4 moles of AgNO₃.
C. 6.2 moles of CaCl₂ will reacts with 6.2×2 = 12.4 moles of AgNO₃.
D. 12.4 moles of CaCl₂ will reacts with 12.4 × 2 = 24.8 moles of AgNO₃
Thus the right answer is 6.2 moles of AgNO₃ will react with 3.1 moles of CaCl₂.
<span>While
treating food with gamma rays kills microorganism by damaging their DNA, the energy
of gamma rays rips off electrons from atoms hence ionizing them (causing free radicals).
However, gamma rays do not make the food atoms radioactive. The body has a natural
mechanism of riding the body of free radicals. However, large quantities of radicals in the body can cause
damage.</span>
