Spectroscope, Valence Shell, Down Syndrome & Chemistry Concepts

Science Q&A: Physics, Biology & Chemistry

What is a spectroscope?

A spectroscope is an instrument used to measure the properties of light within a portion of the electromagnetic spectrum.

What is the valence shell?

The valence shell is the outermost electron shell of an atom; it contains the valence electrons responsible for chemical bonding.

What is Down syndrome?

Down syndrome is a genetic condition caused by the presence of an extra copy of chromosome 21. It is characterized by a variable degree of intellectual disability and distinctive physical features that can make the condition recognizable.

How many chromosomes do humans have?

In humans, each cell normally contains 46 chromosomes arranged in 23 pairs. The first 22 pairs are autosomes, and the 23rd pair are the sex chromosomes (gonosomes).

What are STDs?

Sexually transmitted diseases (STDs), also called sexually transmitted infections (STIs), are infectious diseases caused by various microbes that are commonly transmitted through sexual activity. Some examples, such as hepatitis B and HIV, can also be transmitted through blood.

Chemistry

What is an acid?

An acid is any chemical compound that, when dissolved in water, produces a solution with a higher concentration of hydronium ions than pure water (i.e., a pH less than 7).

What is pH?

pH is a measure used in chemistry to indicate the acidity or alkalinity of a substance, usually in solution. The most accurate way to measure pH is with a pH meter using two electrodes: a reference electrode and a glass (indicator) electrode.

What is binding energy?

Binding energy is the average total energy released when one mole of chemical bonds forms from its constituent fragments; equivalently, it is the average total energy required to break one mole of those bonds.

• Major chemical bond types include covalent, metallic, and ionic bonds.

What is an alcohol?

An alcohol is an organic compound derived from alkanes in which a hydroxyl group (-OH) replaces a hydrogen atom bonded to a carbon. Alcohols can be classified as primary, secondary, or tertiary depending on the number of carbon atoms attached to the carbon bearing the hydroxyl group. A common example is ethanol: CH3CH2OH.

What is electron configuration?

In chemistry, electron configuration describes the arrangement of electrons in an atom, molecule, or other physical system according to the orbital approximation, where the system's wave function is expressed as a product of antisymmetrized orbitals.