Covalent bond (molecular bond): a chemical bond that involves the sharing of electron pairs between atoms.
1. Non-polar covalent bond: the electrons are shared equally between atoms
ex: CH₄ (methane)
2. Polar covalent bond: the electrons are not shared equality between atoms
ex: H₂O (water)
Ionic bond: a chemical bond formed between two ions with opposite charges
ex: NaCl (sodium chloride)
To know the difference between ionic and covalent bonding, one must first understand the chemical difference between sharing electrons and being attracted by charges to one another.
Every atom wants to fulfill the octet rule, or, getting to a stable 8 electrons in its outermost shell. (Having 8 valence electrons)
Atoms in covalent bonds do this by sharing electrons. A good analogy to express this would be if there was a toy that we both wanted, but there was only one of them. Instead of you or I having it to ourselves, we would share. This is what atoms in covalent bonds do.
Atoms in ionic bonds do this by transferring electrons. Sodium loses an electron and chlorine gains an electron (becoming chloride). This is like you taking the toy to yourself. Now because sodium is now a positive ion and chloride is a negative ion, the two come together because opposite charges attract.
I really hope this helps!
Best wishes!:)
A scientific theory is a broad explanation for events that is widely accepted as true. Evolution is a change in species over time. Evolution occurs by natural selection. The cell theory states that all living things are made up of cells, and living cells always come from other living cells.
B- Electron transport chain
Answer:
an exchange of homologous segments between homologous chromosomes.
Explanation:
Crossing over happens during meiosis, during this process the two homologous chromosomes cross over each other, resulting in the exchange of genetic information giving rise to a mixture parental genetic materials.
Answer:
C
Explanation:
C is the only answer that is acceptable. The evidence does not support the hypothesis. It is the best reason for not accepting something as fact.
D is not a good answer. Consensus sometimes plays a role in a scientific decision: no one would seriously propose that "The Earth is Flat" isn't ruled by consensus, but it is also proven wrong other ways.
B is not the reason Nessy isn't accepted. It is a lack of clear undisputable evidence that is the problem
A The quotation says that there is shadows and movements in the lake, but no other signs of Nessy
