Ap Biology (copy)

What is matter?

Anything that takes up space and has mass; composed of atoms.

What is a chemical substance?

A material with a definite chemical composition, can be an element or a compound.

What defines an element?

A pure substance that cannot be broken down into different types of substances.

What are atoms?

The smallest particles of an element.

What is the nucleus of an atom?

The center of an atom holding protons and neutrons.

What is an ion?

An atom that gains or loses electrons and carries a positive or negative charge.

How are neutrons and protons weighed?

They have almost the same mass, about 1 Dalton, while electrons have a negligible mass.

What does the atomic number represent?

The number of protons in the nucleus of an atom, determining the element's identity.

What is the formula for calculating how many electrons can fit in a shell?

2(n)² where n is the number of the shell.

What is a covalent bond?

The sharing of a pair of valence electrons by two atoms.

What is meant by a measure of central tendency?

It refers to mean, median, and mode, which summarize a set of data.

How is the mean calculated?

By dividing the total sum of the data set by the number of samples.

What does standard deviation indicate?

How spread out the data is from the mean.

What is a radioactive isotope?

An isotope whose nucleus decays quickly, giving off particles and energy.

What is the significance of valence electrons?

They determine the chemical behavior of an atom.

What is the cell theory's modern definition?

All living things are made up of cells, and cells come from preexisting cells.

What is the cubic square law?

As a shape grows, its volume increases faster than its surface area, limiting cell size.

What happens to the range when data spreads out more?

The range increases.

What does the standard error of the mean tell you?

How far the sample mean is likely to be from the true population mean.

What is a chemical reaction?

A process that changes some chemical substances into other substances.

What is the difference between active cells and inactive cells?

Active cells have more folds on their membrane for increased surface area.

What is the purpose of error bars in graphs?

To represent the uncertainty or variability of data.

What defines a molecule?

A group of two or more covalently bonded atoms.