Answer:Any change that occurs without altering the chemical composition of a substance is a physical change. Physical changes can include changing the color, shape, state of matter, or volume of a substance. It is crucial to remember that physical changes never alter the chemical makeup.
Explanation:
i hope that helps u try to figure it out a little bit sorry i couldn't find your answer i didn't have much to go off of 
 
        
             
        
        
            
            
                Which of these is an isoelectronic series? 1) na+, k+, rb+, cs+ 2) k+, ca2+, or, s2– 3) na+, mg2+, s2–, cl– 4) li, be, b, c 5) n 
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An isoelectronic series is where all of the ions listed have the same number of electrons in their atoms. When an atom has net charge of zero or neutral, it has equal number of protons and electrons. Hence, it means that the atomic number = no. of protons = no. of electrons. If these atoms become ions, they gain a net charge of + or -. Positive ions are cations. This means that they readily GIVE UP electrons, whereas negative ions (anions) readily ACCEPT electrons. So, to know which of these are isoelectronic, let's establish first the number of electron in a neutral atom from the periodic table:
Na=11; K=19; Rb=37; Cs = 55; Ca=20; S=16; Mg=12; Li=3; Be=4; B=5; C=6
A. Na⁺: 11-1 = 10 electrons
     K⁺: 19 - 1 = 18 electrons
     Rb⁺: 37-1 = 36 electrons
B. K⁺: 19 - 1 = 18 electrons
    Ca²⁺: 20 - 2 = 18 electrons
    S²⁻:  16 +2 = 18 electrons
C. Na⁺: 11-1 = 10 electrons
    Mg²⁺: 12 - 2 = 10 electrons
     S²⁻:  16 +2 = 18 electrons
D. Li=3 electrons
    Be=4 electrons
    B=5 electrons
    C=6 electrons
The answer is letter B.
        
             
        
        
        
Answer:
D
Explanation:
the answer is d white precipitate
 
        
                    
             
        
        
        
Bottle 1 is a compound bottle 2 is element bottle 3 is a element bottle 4 is a element