Zeff = Z - S
Here, Z is the number of protons in the nucleus, that is, atomic number, and S is the number of nonvalence electrons.
For boron, the electronic configuration is 1s₂ 2s₂ 2p₄
Z = 5, S = 2
Zeff = 5-2 = +3
For O, electronic configuration is 1s₂ 2s₂ 2p₄
Z = 8, S = 2
Zeff = 8-2 = +6
Hence, the correct answer is second option, that is, +3 and +6, the Zeff of boron is smaller in comparison to O, thus, boron exhibits a bigger size than O.
Glass doesn't contain planes of atoms that can slip past each other, so there is no way to relieve stress. It has many microscopic cracks that act as seeds for fracture. It’s molecular structure is composed of tetrahedral crystals so it ruptured easily under stress
Answer:is 1.08 kg
Explanation:
Just got it wrong and it gave me the answer
I don't know the answer. Can I ask your help to answer that question? pls.
Explanation:
The given reaction is redox reaction but not combustion reaction.
Redox reaction : It is a chemical reaction in which oxidation and reduction occurs simultaneously.Oxidation is gaining of electrons and reduction is loosing of electrons.
oxidation
reduction
Potassium when reacts with water ,gives potassium ion in aqueous medium and combines with hydroxide ion present in water to form potassium hydroxide where as 
ions of water by gaining electrons (from potassium in water) gives hydrogen gas.
Hence , yes it is a redox reaction
Combustion reaction are the chemical reaction in which one reactant react with oxygen molecule to give heat and light.
Here in given reaction no oxygen molecule is appearing on reactant side.
Hence not a combustion reaction.
