Answer:
option A is correct  ( sodium, calcium and barium)
Explanation:
Given compounds:
Sodium chloride , calcium sulfide, barium oxide
We know that metals form positive ions. In order to solve the problem we must identify the metals from given compounds.
Na⁺Cl⁻
Ca²⁺S²⁻
Ba²⁺O²⁻
We can see that sodium, calcium and barium contain positive charges.
Thus option A is correct.
Because sodium have one valance electron. When it combine with chlorine sodium lose its one electron to complete the octet and chlorine accept it to complete its octet. Thus sodium form positive ion and chlorine form negative ion.
Similarly barium and calcium are present in group 2. Both have two valance electron. When they lose them cation are formed.
Other option are incorrect because,
Option B have sulfur and oxygen which are anion.
Option C have chlorine which is also anion
Option D have chlorine, sulfur and oxygen that are anions.
 
        
             
        
        
        
What is reflux? isn't it like when u aren't able to digest something?
        
             
        
        
        
Answer:
Explanation:
exothermic reactions involve release of heat whereas endothermic reaction involve absorption of heat.
 
        
                    
             
        
        
        
Atoms do not always contain the same number of electrons and protons, although this state is common. When an atom has an equal number of electrons and protons, it has an equal number of negative electric charges (the electrons) and positive electric charges (the protons). The total electric charge of the atom is therefore zero and the atom is said to be neutral. In contrast, when an atom loses or gains an electron (or the rarer case of losing or gaining a proton, which requires a nuclear reaction), the total charges add up to something other than zero.
        
             
        
        
        
The statement which best describes the development of theories that connected microscopic and macroscopic phenomena is; <em>q</em><em>It took several hundred years for scientists to develop current theories, and they are still being revised to </em><em>this.</em>
<em>Discussion</em><em>;</em>
Most scientific theories involving microscopic and macroscopic phenomenon have taken several years to be developed; however, this theories are still under revision till date.
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