I belive its D if not right sorry.
Answer:
Scientific Question: ... I will boil water and add a substance like salt to see if the boiling point increases.
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:
C2H4O2 + 2O2 ==> 2CO2 + 2H2O
Explanation:
Start with the carbons
C2H4O2 + O2 ==> 2CO2 + H2O There are 2 on the left, so you need 2 on the right.
Next deal with the hydrogens. You have 4 on the left so you have to make 4 on the right
C2H4O2 + O2 ==> 2CO2 + 2H2O
The oxygens are the real devil in this question. Be careful how you handle them. There are 2 * 2 = 4 from the CO2 and 2*1 = 2 from the water. The total is 6
Now you can't just put a 3 in front of the O2. There are 2 in the given chemical. So you don't need 6. You need 6 -2 = 4. But the oxygen is O2. You have to divide the 4 by 2 to get 2
C2H4O2 + 2O2 ==> 2CO2 + 2H2O
And that's your answer.
