Answer: Elements in Group 2
Explanation: The periodic table was arranged by Dmitri Mendeleev specifically around similarites in their chemical behaviors. He found that as atomic number increases, at some point an element starts to react in a manner similar to a previous one. When that happened, he would place the larger element under the smaller one, and eventually noticed a periodicity in the table. Elements in a column (Groups) had similiar chemical properties. We know today that these similarities are due to the electron configuration, and that these configurations repeat themselves. He left gaps in the table when he could find an existing element with properties similar to others in that group. I big leap of faith, but it worked. Elements for those missing boxes were eventually discovered.
Lose electrons - electrons want to fill their outer valence shell, so sometimes instead of gaining it is easier to lose some and have a filled outer shell
Answer:
0.05 mol
Explanation:
The balanced equation for the reaction that takes place is:
- 2C₂H₂ (g) + 5O₂ (g) → 4CO₂ (g) + 2H₂O (g)
Now we<u> convert 0.10 moles of carbon dioxide (CO₂) into moles of acetylene (C₂H₂)</u>, using the <em>stoichiometric coefficients of the balanced reaction</em>:
- 0.10 mol CO₂ *
= 0.05 mol C₂H₂
Your answer is B because elements within the same column have equal numbers of valence electrons which determines the reactivity of an element.
Fe
Cobalt
Sodium
Sn
Phosphorus
Florine
I don’t know
Mg
I don’t know
Calcium
C
Pb
Silver
Zinc
Nickel
