Bio-H Chapter 2: Life's Chemical Basis

atomic number

Number of protons in the atomic nucleus.

What does the atomic number determine?

which element atom is

electron

Negatively charged subatomic particle

element

A pure substance that consists only of atoms with the same number of protons.

isotopes

Forms of an element that differ in the number of neutrons their atoms carry.

mass number

Of an isotope, the total number of protons and neutrons in the atomic nucleus

neutron

Uncharged subatomic particle that occurs in the atomic nucleus.

nucleus

Central core of an atom.

periodic table

Tabular arrangement of all known elements by their atomic number.

proton

Positively charged subatomic particle that occurs in the nucleus of all atoms.

radioactive decay

Process in which an atom emits energy and/or subatomic particles when its nucleus spontaneously breaks up.

radioisotope

Isotope with an unstable nucleus

A substance with a detectable component

tracer

subatomic particles

protons, neutrons, electrons

The negative charge of an electron is of the same ___ as that of a proton.

magnitude

Most atoms have ___ number of electrons as they have protons

the same

An atom with an equal amount of electrons and protons has…

no charge

Each of the 118 known elements is represented by a ___ that is an ___ of its name.

symbol; abbreviation

___ that is an ___ of its name.

symbol; abbreviation

How many electrons does the most common isotope of carbon have, and what is the typical mass number?

6;12

True or False: A radioisotope decays at an unstable rate which makes it hard to predict.

false

14C

the radioisotope of carbon

What happens to carbon-14 when it decays?

Its neutrons split into a proton and an electron, emitting the electron as radiation.

What does carbon-14 (14C) become after decay?

It becomes nitrogen-14 (14N), with seven neutrons and seven protons.

How many protons and neutrons does carbon-14 have?

six protons and eight neutrons.

How do scientists estimate the age of a rock/fossil?

by measuring its isotope content

What does the chemical behavior of an atom arise from?

the number of protons and electrons it has

Why do all isotopes generally have the same chemical properties?

because neutrons GENERALLY have a little effect on chemistry

What is a radioactive tracer?

A molecule in which an atom has been replaced with a radioisotope, allowing it to be detected.

How do researchers use radioactive tracers?

To study biological processes by detecting the radiation emitted during decay.

What is the purpose of a tracer in biological systems?

To follow the substance within a biological system, such as a cell or body.

What is an example of a radioisotope used in tracers?

Carbon-14 (14 C) can replace Carbon-12 (12 C) in a molecule.

What is the detectable component in a radioactive tracer?

The radiation emitted during the decay of the radioisotope.