Biology chapter 2.1

What is the fundamental structural unit of an element?

atom

Which four elements make up approximately 96% of living matter?

carbon, hydrogen, nitrogen, oxygen

Radioactive isotopes are biological tools that are often used to

detect brain tumors and other important medical technologies.

In which scenario below will the electrons have the highest energy

electrons in the outer shell of potassium

A substance with specific properties that cannot be broken down or converted into another substance is called a(n)

element

The atomic number of an atom is defined as the

number of protons in the atomic nucleus

What subatomic particle (s) can be found in the nucleus of the atom?

protons and neutrons

Copper has 29 protons, 34 neutrons, and 29 electrons. What is the atomic number of copper? See Section 2.1 (Page 19) .

29

Iron is an important element in human body cells. If iron has an atomic number of 26, what does this tell you about this element?

An iron atom has 26 protons.

Which of the following best explains the molecular complexity of living organisms?

A small number of monomers can be assembled into large polymers with many different sequences.

How do atoms respond when they absorb energy

Electrons move to a higher orbital

Isotopes are atoms of the same element that have different numbers of protons. True or False?

False

The attractive force that holds two or more water molecules together is an example of an ionic bond.

False

Different types of living matter often have different forms of the same elements in their bodies. For example, the nitrogen in an animal often has a slightly different atomic structure than the nitrogen in a plant. Recently, nutritionists have discovered how to deduce the diets of various animal species by examining the type of nitrogen (and other elements) inside their bodies. What is the chemical basis behind this scenario?

Isotopes of the same element have the same atomic number but different atomic masses.

For an atom to achieve maximum stability and become chemically inert, what must occur?

Its outermost energy shell must be filled with electrons.

Imagine that you have been hired as a chemist and your first task is to examine a newly discovered atom. The paperwork you are given states that its atomic number is 110. What does this mean?

The atom contains 110 protons.

Phosphorus has an atomic number of 15, so what is the distribution of its electrons?

The first energy level has 2, the second has 8, and the third has 5.

What property of an atom determines which element it is? See Section 2.1 (Page 19)

The number of protons

Carbon-14 is often used for carbon dating, where scientists measure the rate of carbon-14 decay to determine the age of items. Carbon-14 contains six protons and eight neutrons. During the process of carbon-14 decay, one of its eight neutrons becomes a proton and an electron is emitted. Which of the following is the best explanation of what has occurred?

The resulting atom is now a different element because the number of protons has changed.