The Great Oxidation Event (GOE), sometimes also called the Great Oxygenation Event, Oxygen Catastrophe, Oxygen Crisis, Oxygen Holocaust,[2] or Oxygen Revolution, was a time period when the Earth's atmosphere and the shallow ocean first experienced a rise in oxygen, approximately 2.4 billion years ago (2.4 Ga) to 2.1–2.0 Ga during the Paleoproterozoic era.[3] Geological, isotopic, and chemical evidence suggests that biologically produced molecular oxygen (dioxygen, O2) started to accumulate in Earth's atmosphere and changed Earth's atmosphere from a weakly reducing atmosphere to an oxidizing atmosphere,[4] causing many existing species on Earth to die out.[5] The cyanobacteria producing the oxygen caused the event which enabled the subsequent development of multicellular forms.
Carbohydrates are ring shaped.
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The elements potassium and sodium have similar chemical properties because they have the same number of valence electrons and form +1 ions.
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II. sulfur (S) and carbon (C)
and
III. fluorine (F) and oxygen (O)
will form covalent bonds, so the answer will be:
e. II and III
Explanation:
To know is what type of bond is formed between atoms we need to look at the electronegativity difference between the atoms.
If the electronegativity difference is less than 0.4 there is a nonpolar covalent bond.
If the electronegativity difference is between 0.4 and 1.8 there is a polar covalent bond. (if is a metal involved we consider the bond to be ionic)
If the electronegativity difference is greater then 1.8 there is an ionic bond.
We have the following cases:
I. lithium (Li) and sulfur (S)
electronegativity difference = 2.5 (S) - 1 (Li) = 1.5 but because there is a metal involved the bond will be ionic
II. sulfur (S) and carbon (C)
electronegativity difference = 2.5 (S) - 2.5 (C) = 0 so the bond will be nonpolar covalent
III. fluorine (F) and oxygen (O)
electronegativity difference = 4 (F) - 3.5 (O) = 0.5 so the bond will be polar covalent bond.
Learn more about:
covalent and ionic bonds
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Answer:
The number before any molecular formula applies to the entire formula. So here you have five molecules of water with two hydrogen atoms and one oxygen atom per molecule. Thus you have ten hydrogen atoms and five oxygen atoms in total.