The water cycle ...........
For your second question its Diamonds,Rubys, Emeralds.
And for your first question its :Minerals are natural: These substances that form without any human help.
Minerals are solid: They don't droop or melt or evaporate.
Minerals are inorganic: They aren't carbon compounds like those found in living things.
Minerals are crystalline: They have a distinct recipe and arrangement of atoms.
A. The number of valence electrons increases as atomic mass increases. == Generally true for the representative elements since atomic mass generally increases with increasing Z.
B. The reactivity of alkali metals increases as atomic mass increases. == True. Atomic mass increases down the column and so does reactivity
C. The reactivity of the halogens increases as atomic mass increases. == False. Reactivity decreases down the column.
D. The number of valence electrons decreases across a period. == False. In general, the number of valence electrons increases across a period, particularly for the representative elements.
<span>H</span>₃<span>PO</span>₄<span> - Phosphoric Acid :
H</span>₃<span>PO</span>₄<span> = 1.0 * 3 + 31.0 + 16.0 * 4 = 98.0 g/mol
hope this helps!</span>
Answer:
Explanation:1/2=5750 years,
1/2=5750 years, 1/2(1/2)=1/4, (1/2)(1/2)(1/2)=1/8, (1/2)(1/2)(1/2)(1/2)=1/6
4 half lives have passed so 4(5750)=23000 years since the tree was chopped down
1000000 atoms (1/2)=500000 atoms(1/2)=250000(1/2)=125000(1/2)=62500 atoms would remain in the wood after 4 half lives
Dinosaurs became extinct around 62 million years ago, so if 14C's half life has a value of 5750 years, it would be gone or in such small amounts that dating would be ineffective today.
As Potassium decays into Argon in 1.3 billion years, apart from volcanic activity, it would enable geologists to effectively date things that are really, really, really old.
