Answer:
A and B
Explanation:
The Sun's Energy is stored in the chemical bonds that make up food. Some forms of life make their own food. These are the Autotrophs.
Plants are autotrophs, which means they produce their own food.
Answer:
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Explanation:
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Following are the chemical elements that have atomic mass greater than 173.5 u and atomic number less than 75.
1. Lutetium
Atomic Number = 71
Atomic Mass = 174.97 u
2. Hafnium
Atomic Number = 72
Atomic Mass = 178.49 u
3. Tantalum
Atomic Number = 73
Atomic Mass = 180.95 u
4. Tungsten
Atomic Number = 74
Atomic Mass = 183.85 u
Answer:
Francium is hypothesized to be the most reactive metal, but so little of it exists or can be synthesized, and the longest half-life of its most abundant isotope is 22.00 minutes, so that its reactivity cannot be determined experimentally.
Explanation:
Francium is an alkali metal in group 1/IA. All alkali metals have one valence electron. As you go down the group, the number of electron energy levels increases – lithium has two, sodium has three, etc..., as indicated by the period number. The result is that the outermost electron gets further from the nucleus. The attraction from the positive nucleus to the negative electron is less. This makes it easier to remove the electron and makes the atom more reactive.
Experimentally speaking, cesium (caesium) is the most reactive metal.
Answer:
0,0,0,0
Explanation:
The formal charge formula:
So:
Hydrogen: 1 elec. of valence and shares two electrons with the O
Oxygen: 6 elec. of valence, 2 lone pairs and shares two electrons with the H and two with the F
Fluorine: 7 elec. of valence, 6 lone pairs and shares two electrons with the O
Oxygen: 6 elec. of valence, 3 lone pairs
Note: the dative bond between F and the second O doesn't count as shared electrons.
