OnRamps Biology Unit 1

What is electronegativity?

A measure of how strong an atom pulls electrons toward its nucleus

T/F: the elements of life have high electronegativity values

True, life is very chemically reactive

T/F: Elements in group 8 are chemically active

False, group 8 elements have a full outer shell (an octet)

What are the elements crucial to life?

Carbon, hydrogen, nitrogen, oxygen, phosphorus, and sulfur, often referred to as CHNOPS.

Where are protons found?

The nucleus of an atom

What determines the behavior of a chemical?

The arrangement of the valence electrons

In a neutral atom, how do you find the number of electrons?

You look at the atomic number, which is also the number of protons.

How many electrons does each shell hold?

Each shell can hold a maximum of $2n^2$ electrons, where $n$ is the principal quantum number (shell level). For example, the first shell (n=1) holds 2 electrons, the second shell (n=2) holds 8 electrons, and the third shell (n=3) can hold 18 electrons.

How do you find the number of protons?

You look at the atomic number

What is the atomic number?

The atomic number is 35

Which is the mass number?

The mass number is 35.

What do isotopes differ by?

Isotopes differ by mass, specifically the number of neutrons.

What is an isotope?

A variant of a chemical element that has the same number of protons but a different number of neutrons, resulting in a different mass number.

T/F: The number of electrons equals the number of protons in an ion

False; in an ion, the number of electrons is different from the number of protons.

Where are neutrons found?

Neutrons are found in the nucleus of an atom, along with protons. They contribute to the atomic mass but have no charge.

What is a charged atom called?

An ion

What is the octet rule?

An atom becomes more stable when its outermost shell is full with 8 total electrons

F^-1 has how many electrons?

It has 10 electrons, as it gains one to become negatively charged.

T/F: Electrons line up as pairs once there are more than 4 electrons in a shell

True, electrons line up in pairs past 4 electrons in a shell

T/F: Elements within a group have a similar valence electron number and will behave in a similar fashion

True, elements in the same group of the periodic table have the same number of valence electrons, leading to similar chemical properties.

Pure covalent bond

A chemical bond that forms when two atoms with identical or very similar electronegativities share a pair of electrons equally, as seen in diatomic molecules like $H<em>2$ and $Cl</em>2$.

Ionic Bond formation

Forms between atoms of full opposite charge due to complete electron transfer

What type of bond is intramolecular?

Covalent bond

T/F: All bond types besides covalent are intermolecular

True, covalent are intra not intro

Intermolecular Forces

Various forces that exist between atoms, molecules, and ions. Very weak forces, can usually be overcome by the motion of the molecules. These forces usually encompass interactions related to polarity or attractive forces

Dipole-dipole forces

Forces between permanently polar molecules, always have a partial positive and partial negative charge

Hydrogen bonding

A strong bond that must occur only between Fluorine, Oxygen, or Hydrogen

Dispersion Forces

Forces between non polar molecules that are based on temporary dipole movements where very quick partial positive and negative forces create slight attraction

Monomer

Repeated units that make up proteins, carbs, and nucleic acids (all of which are macromolecules)

Anabolic reactions

Require energy as the dehydration synthesis combines the monomers into larger molecules

Catabolic reactions

Release energy as the monomers are broken apart by hydrolytic reactions

Fats

type of lipid that form from the covalent additions of 3 carbon chains (aka fatty acids)

Carbon Fixation

the process of converting inorganic carbon dioxide into organic compounds, such as glucose, during photosynthesis.

How many covalent bonds can carbon form?

4 covalent bonds

Functional groups

combinations of atoms that are bonded together and work as a single unit

The Carboxyl Group

A functional group characterized by a carbon atom double bonded to an oxygen atom and single bonded to a hydroxyl group. It plays a key role in forming amino acids and fatty acids. Look for COOH or COO^-

The Amino Group

A functional group comprised of a nitrogen atom bonded to two hydrogen atoms and the carbon skeleton. The amino group will accept a positively charged proton, results in the group adopting a positive charge. Look for NH₃⁺ or NH₂

Bases

Substances that can accept protons or donate electron pairs in reactions. They typically increase the pH of a solution.

Dehydration Synthesis

A chemical reaction that links monomers together to form a polymer by removing a molecule of water. During this process, a hydroxyl (-OH) group from one monomer and a hydrogen atom from another monomer combine to release water, leaving behind a covalent bond between the monomers.

Hydrolysis

A chemical reaction that involves the addition of water to break covalent bonds between molecules, facilitating the breakdown of polymers into monomers. A water molecule is split into a hydroxyl group (-OH) and a hydrogen ion (H⁺). These components are added to the polymer, breaking the covalent bond and separating the monomers.

Hydrophilic

Having a strong affinity for water, these types of substances readily interact with water molecules, often dissolving in water.

Hydrocarbons

Organic compounds composed of only hydrogen and carbon, hydrophobic in nature and insoluble in water. The simplest type of organic molecules. They can have single, double, or triple covalent bonds between carbon atoms, which determines their properties. The arrangement of these is essential to determining their functions, like enzyme activity, energy storage, and genetic information storage.

Molecular geometry

The three-dimensional arrangement of atoms within a molecule, which influences physical and chemical properties.

Valence Shell Electron Pair Repulsion (VSEPR) Theory

Predicts molecular geometry based on the arrangement of valence electron pairs around the central atom. Electron pairs, whether bonding or lone pairs, repel each other to achieve a stable geometry.

Electron domains

Regions around a central atom where electrons are likely to be found, including bonding pairs and lone pairs.

Lone pairs

Electrons that are not involved in bonding and occupy space around the central atom, influencing molecular geometry.

Polymerization

A process in which monomers join together through covalent bonds to form large molecules known as polymers.

Protists

A eukaryotic group of organisms, are the ancestors of all plants and materials

Emergent properties

Characteristics that arise when individual components interact in complex ways, leading to new functions or behaviors.

T/F: Viruses are not alive

True, viruses are not alive because they cannot perform metabolic actions

T/F: Eukaryotes can be multicellular or unicellular

True, eukaryotes can exist as either multicellular organisms, like animals and plants, or unicellular organisms, like yeast and protists.