Chemical Bonds and Energy

These flashcards cover key concepts regarding chemical bonds, energy, and their roles in biological processes.

What are chemical bonds?

Interactions between atoms that involve sharing, donating, or receiving electrons.

Why are chemical bonds important in biology?

Biology heavily relies on chemistry; reactions like cellular respiration and neurotransmitter production are chemical processes.

What is the Bohr model?

An oversimplified model of the atom with nucleus and electrons in fixed orbits around it.

How do the number of valence electrons affect the reactivity of elements?

The closer an element is to having eight valence electrons, the more stable it is and less reactive.

What does the octet rule state?

Elements with eight valence electrons in their outer shell are considered stable.

What is a noble gas?

Elements like neon and argon that rarely interact because their outer shells are full.

What happens to sodium in terms of reactivity?

Sodium has one outer electron that it wants to lose, making it very reactive.

What is sodium chloride?

A stable compound formed when sodium donates an electron to chlorine.

What kind of bond is formed between sodium and chlorine?

An ionic bond due to sodium donating an electron to chlorine.

What is a covalent bond?

A bond where two atoms share one or more pairs of electrons.

Can you give an example of a covalent bond?

An oxygen molecule (O2) is created by two oxygen atoms sharing electrons.

What are polar covalent bonds?

Bonds where electrons are shared unequally, leading to partial charges on atoms.

What is a polar molecule?

A molecule like water that has a slight positive charge on one end and a slight negative charge on the other.

What are hydrogen bonds?

Weak bonds that occur between hydrogen and another electronegative atom, such as oxygen.

What is an exergonic reaction?

A reaction that releases energy when bonds are broken.

What happens during cellular respiration?

It releases energy from sugar into a form usable by cells, such as ATP.

What is an endergonic reaction?

A reaction that absorbs energy to create products rich in potential energy.

What is a perfect example of an endergonic process?

Photosynthesis, where sunlight energy is absorbed to create glucose.

What happens in metabolism?

It includes all the chemical reactions in an organism that break down or build complex molecules.

What is the role of metabolic pathways?

Series of reactions that build or break down molecules, releasing energy gradually.

How does sodium react with water?

It reacts violently, showing its high reactivity and makes sodium highly unstable.

Why do water molecules have special properties?

Their polar nature and the presence of hydrogen bonds contribute to surface tension and high specific heat.

What are covalent bonds between two hydrogen atoms an example of?

They are an example of true covalent bonds where electrons are shared directly.

What can be observed when breaking carbon and hydrogen bonds?

Energy is released, providing light and heat, like in a candle flame.

What characterizes an ionic compound like sodium chloride?

It forms from the transfer of electrons resulting in the stability of the compound.

How does the structure of water affect its function in living organisms?

Its polar nature allows it to interact with various substances crucial for life.