Indian army has published the notification for SSC Tech 56 men and SSC Tech 27 women for the course commencing at OTA Chennai from April 2021
Find the number of proton, electrons and neutrons in 13AL2
In an atom 13Al27 number of protons is (a), electron is (b) and neutron is (c). Hence their ratio will be: [in order c : b : a]
13 : 13 : 14
14 : 13 : 13
13 : 14 : 13
14 : 13 : 14
Which one of the following is a transition metal?
Aluminium (Al)
Manganese (Mn)
Magnesium (Mg)
Calcium (Ca)
Which one of the following gases, present in the air near the surface of the Earth, has maximum concentration?
Oxygen (O2)
Hydrogen (H2)
Nitrogen (N2)
Methane (CH4)
Which one of the following is a chemical change?
Dissolving sugar in water
Melting of ice
Crystallization
Milk turning sour
Which of the following represents a chemical change?
Explosion of a firework.
Rusting of iron.
Magnesium burns in air leaving behind a powdery ash.
Which one among the following is the correct order of reactivity of the elements?
Cu > Mg > Zn > Na
Na> Zn > Mg > Cu
Na > Mg > Zn > Cu
Cu > Zn > Mg > Na
