Permanent hardness of water can be removed by?
filtration
adding slaked lime
adding caustic soda
boiling
Correct answer is C
- this hardness cannot be removed by boiling. We can remove this hardness by treating the water with washing soda, caustic soda and permutit
A noble gas with a high power of fog penetration used in aerodrome beacons is?
krpton
argon
helium
neon
Correct answer is D
No explanation has been provided for this answer.
12D + 13T → 24He + 01n + energy
The reaction above illustrates?
alpha decay
artificial transmutation
nuclear fussion
nuclear fission
Correct answer is C
No explanation has been provided for this answer.
Elements in the same period in the periodic table have the same?
number of shells
atomic number
chemical properties
physical properties
Correct answer is A
Elements within the same group have the same number of electrons in their valence (outermost) shells, and they have similar electron configurations. They exhibit similar chemical properties.
But elements in the same period can determined by the same number of shells.
The maximum number of electrons in the L shell of an atom is?
2
8
18
32
Correct answer is B
The maximum number of electrons present in a particular shell is calculated by the formula 2n2, where “n” represents the shell number. For instance, K shell is the first shell and it can hold up to 2(1)2 = 2 electrons. Similarly, L shell is the second shell and it can hold up to 2(2)2 = 8 electrons.