Answer:
atomic structure
Explanation:
Its pretty obvious. Nothing here can test atomic structure. You can test melting point, with a hot plate. You can test the ability to dissolve something with the container of water. You can test brittleness  with the hammer.
 
        
                    
             
        
        
        
Answer:
Is this math? Cause as a fourth grader, I can do Algebra, but not this.
Explanation:
 
        
             
        
        
            
            
                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 
                ss7ja [257]             
         
        
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.
        
             
        
        
        
<span>The only scenario that
will allow you to reach an equilibrium mixture involving these chemicals is to
place NH3 into a sealed vessel. This reaction requires pressures between 2100,
3600 psi, and temperatures between 300 and 550 degree Celsius. With this given
temperature and pressure, the ammonia naturally decomposes into nitrogen and
hydrogen gas at the same rate. When this happen, the concentrations of these
chemicals become constant and the system is said to be at equilibrium.</span>