I think its answer A. (hope its right)
The definition of authentic is something that is original or true and not a copy of anything else.
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Three scientists are credited with the development of cell theory. Matthias Schleiden observed that all plants were made of cells; Theodor Schwann observed that all animals were also made of cells; and Rudolf Virchow observed that cells only come from other cells.
Density of any substance is defined as mass per unit volume of that substance.
Density of air is inversely proportional to the altitude. This means that as the altitude increases, the density of air decreases, and vice versa.
Based on this, examining the choices given, we can conclude that the density of air is greater at sea level.
Answer:
Explanation:
The chlorine is present in group 17. It has seven valance electrons. It accept one electron to complete the octet and show -1 charge and from anion.
Cl⁻
Sodium is present in group one. It alkali metal. It loses one valance electron and show +1 charge. It form sodium cation.
Na⁺
Magnesium is present in group two. It loses its two valance electrons and show +2 charge. It form magnesium cation.
Mg⁺²
Oxygen is present in group 16. It has six valance electrons. It require two electrons to complete the octet and show -2 charge.
O⁻²
Aluminium is present in group 13. it has three valance electrons. It loses its three valance electrons and show +3 oxidation state
Al⁺³ (most common)
others = Al⁺¹, Al⁺²
Iron is present on group eight.
Fe⁺² , Fe⁺³ (most common)
others = Fe⁺⁴, Fe⁺⁵
Copper is present in group eleven.
Cu⁺¹ Cu⁺²
other = Cu⁺³
Zinc is present in group twelve. -2, 0, +1 , +2
Zn⁻², Zn⁺¹, Zn⁺²