Answer:
Group IA elements have only one valency electron while Group IIA have two valency electrons.
Group IA elements have cations with higher charge density hence polarizing anions easier resulting into covalent character while Group IIA elements have cations with lower charge density hence difficulty in distorting anions resulting into a ionic character. This is due to difference in cationic radii and charges
Answer:
4.981 MeV
Explanation:
The quantity of energy Q can be calculated using the formula
Q = (mass before - mass after) × c²
Atomic Mass of thorium = 232.038054 u, atomic of Radium = 228.0301069 u and mass of Helium = 4.00260. The difference of atomic number and atomic mass between the thorium and radium ( 232 - 228) and ( 90 - 88) show α particle was emitted.
1 u = 931.494 Mev/c²
Q = (mass before - mass after) × c²
Q = ( mass of thorium - ( mass of Radium + mass of Helium ) )× c²
Q = 232.038054 u - ( 228.0301069 + 4.00260) × c²
Q = 0.0053471 u × c²
replace 1 u = 931.494 MeV/ c²
Q = 0.0053471 × c² × (931.494 MeV / c²)
cancel c² from the equation
Q = 0.0053471 × 931.494 MeV = 4.981 MeV
The flow of electricity in a certain path is the circuit.
is the intensity of the sound.
Answer: Option B
<u>Explanation:</u>
The range of sound intensity that people can recognize is so large (including 13 magnitude levels). The intensity of the weakest audible noise is called the hearing threshold. (intensity about
). Because it is difficult to imagine numbers in such a large range, it is advisable to use a scale from 0 to 100.
This is the goal of the decibel scale (dB). Because logarithm has the property of recording a large number and returning a small number, the dB scale is based on a logarithmic scale. The scale is defined so that the hearing threshold has intensity level of sound as 0.

Where,
I = Intensity of the sound produced
= Standard Intensity of sound of 60 decibels = 
So for 19 decibels, determine I as follows,



When log goes to other side, express in 10 to the power of that side value,


Answer:
They are conductors/conductive. Materials that can transfer thermal energy well are conductive.
Explanation: