Biology 2.1

What is a diatomic molecule? given an example

a diatomic molecule is a two atom molecule oxygen or O2

A helium atom has 2 protons and 2 neutrons; how many electrons does it have?

2

Are charges that repel each other like or unlike?

Like

Describe Bohr's atomic model?

The model of the atom developed by Bohr shows that an atom's electrons are located outside the nucleus in regions called energy levels

How many different elements and how many total atoms are in KCl

Two elements, Potassium and Chlorine and two atoms (one each for Potassium and Chlorine)

what two things happen when an atom become an ion?

an atom becomes an ion when its number of electrons changes and it gains an electrical charge

What are compounds consisting only of ions called?

ionic compounds

when do ions form?

ions form when atoms gain or lose electrons

atom

smallest basic unit of matter

A helium atom has 2 protons and 2 neutrons; what is its atomic number

2

The mass number of an atom with 12 protons and 12 neutrons is what?

24

The atomic number of Carbon is 6. How many protons are there in a Carbon atom

6

The maximum number of electrons that can be held in an atom's second energy level is?

8

How elements occur naturally on Earth?

91, 25 of which are found in organisms

Describe the formation of an ionic compound

A compound which is held together by ionic bonds; composed of one or more cations (+ charged ions) and one or more anions (- charged ions). Table salt is an example of an ionic compound. Sodium and chlorine ions come together to form sodium chloride, or NaCl. The sodium atom in this compound loses an electron to become Na+, while the chlorine atom gains an electron to become Cl-. Together, they form a neutral compound because the ions balance each other out. This is true for all ionic compounds - the positive and negative charges must be in balance

When does a covalent bond form?

A covalent bond forms when atoms share a pair of electrons

Which is an example of matter: air or heat?

Air

Why does the study of living things also involve the study of chemistry?

All organisms depend on many chemicals and chemical reactions to live. For instance, animals and plants produce specialized chemicals to help them to consume and digest their prey/food

What do you know about atoms that have gained electrons?

An atom that GAINS 1 or more electrons becomes a negatively charged ion because it has more electrons than protons

When an atom loses electrons its outer energy level what do you know about its charge?

An atom that LOSES one or more electrons becomes a positively charged ion because it has more protons than electrons

Describe what typically happens to atoms with a nearly full outer energy level.

An atom with a nearly full energy level tends to gain electrons

How does an ionic bond form?

An ionic bond forms through the electrical force between oppositely charged ions

What is the difference between an ionic bond and a covalent bond?

An ionic bond forms through the electrical force between oppositely charged ions. A covalent bond forms when atoms share a pair of electrons

What do you call the smallest part of an element that is still that element

Atom

What do you call the total mass of protons and neutrons?

Atomic Mass

A difference in the What of atoms means the atoms are of different elements?

Atomic Number

What do you call the total number of protons in the nucleus

Atomic Number

Which are an example of the building blocks of matter: atoms or compounds?

Atoms

Describe atoms in covalent bonds

Atoms share pairs of electrons in covalent bonds

What makes up the other 4%?

Calcium, Phosphorus, Potassium, Sulfur, Sodium, and several other trace elements

Describe the structure of a molecule of carbon dioxide or CO2

Carbon dioxide has a total of 1 Carbon atom and 2 Oxygen atoms. Each Oxygen atom has 6 valence electrons whereas the Carbon atom only has 4 valence electrons. To satisfy the Octet Rule, Carbon needs 4 more valence electrons. Since each Oxygen atom has 3 lone pairs of electrons, they can each share 1 pair of electrons with Carbon; as a result, filling Carbon's outer valence shell (Satisfying the Octet Rule).

COVALENT - What does the prefix "co" mean and where does "valent" come from?

Co means together and valent comes from a Latin word meaning power or strength

Give an example of a property of an ion based on its charge?

Compounds consisting only of ions (ionic compounds) easily dissolve in water

Is a molecule held together by ionic or covalent bonds?

Covalent

What do we know about the strength of covalent bonds?

Covalent bonds are usually very strong. The more covalent bonds, the stronger the overall bond. A triple covalent bond is stronger than a double covalent bond which is stronger than a single covalent bond.

What do you call a negatively charged atomic particle

Electron

What do you call the space where electrons may be found?

Electron Cloud

Negatively charged particles that move around the atom's nucleus are called what?

Electrons

Two atoms may form several covalent bonds to share several pairs of what? Protons or Electrons?

Electrons

What are the names of the particles outside of the nucleus?

Electrons

Is the exact position of electrons known? this would be a good idea for a science experiment if you were a biologist or chemist

Electrons are somewhere in a three-dimensional electron cloud around the nucleus

What do you call substances made up of only one kind of atom: isotopes or elements?

Elements

how are elements different from compounds?

Elements: an element is one particular type of atom and it cannot be broken down into a simpler substance by ordinary chemical means Compounds: is a substance made of atoms of different elements bonded together in a certain ratio

True or False: An atom becomes an ion when its numbers of protons change?

False

True or False: Some ions are positively charged and some ions have no charge

False

A negative ion is formed when an atom does what?

Gains one or more electrons

We know that ions play large roles in organisms give some examples...

Hydrogen ions (H+) are needed for the production of usable chemical energy in cells AND Calcium ions (CA 2+) are necessary for every muscle movement in your body AND chloride ions (Cl-) are important for a certain type of chemical signal to the brain

Are protons found outside or inside the nucleus?

Inside

How are ionic compounds held together?

Ionic compounds are held together by ionic bonds

Why do ions form?

Ions form because an atom is more stable when its outermost energy level is full

When do ions usually form?

Ions usually form when electrons are transferred from one atom to another....so it says when they usually form, do you know when else an ion can form? let me know because I do not know...

Is Carbon-14 an isotope or an element of carbon

Isotope

explain why a hydrogen atom can become either an ion or a part of a molecule...

It can become an ion because it can lose or gain an electron. It can become a part of a molecule because it can form covalent bonds with other atoms to gain a full valence shell.

What do you know about salt or sodium chloride (NaCl)?

It is an ionic compound of Na+ and Cl-.

What is the definition of the nucleus of an atom?

It is the dense center of an atom and contains protons and neutrons but no electrons

Do electrons have less, more or the same mass as protons or neutrons?

Less

A positive ion is formed when an atom does what?

Loses one or more electrons

Two atoms of the same element that have different what? are called isotopes of the element

Mass Numbers

What kind of charge do electrons carry?

Negative charge

What do you call an atomic particle with no charge?

Neutron

Isotopes are atoms of the same element that different numbers of what?

Neutrons

Isotopes are atoms that have the number of protons but a different number of?

Neutrons

What are the names of the particles in the nucleus that have no charge?

Neutrons

Is an isotope a subatomic particle?

No

The center of an atom is called?

Nucleus

Share pairs of electrons fill the innermost or outermost energy levels of bonded atoms

Outermost

Name the 6 most common elements in living things?

Oxygen, Carbon, Hydrogen, Nitrogen, Calcium, and Phosphorus

What four elements make up 96% of the human body's mass?

Oxygen, Hydrogen, Carbon, Nitrogen

The nucleus of an atom has what kind of charge?

Positive

What do you call a positively charged atomic particle

Proton

The atomic number of an atom is equal to the number of What in its nucleus?

Protons

What forms the atomic nucleus?

Protons and Neutrons

Covalent bonds are generally strong or weak

Strong

Not all atoms easily gain or lose electrons instead what happens?

The atoms of many elements share pairs of electrons

What is the importance of the charge in ions?

The charge gives ions certain properties

What determines the properties of an element?

The electrons in the atoms

The number of covalent bonds that form depends on...

The number of valences needed to be shared to fill the Octet rule of 8. Single, Double, or Triple bonds may be formed to complete the Octet Rule.

What do we know about the location of shared pairs of electrons?

The shared pairs of electrons fill the outermost energy levels of the bonded atoms

When an atom becomes an ion what determines the type of ion that is formed?

The type of atom that forms depends on the number of electrons in an atom's outer energy level

What determines whether an atom becomes a positive ion or a negative ion?

The type of ion that forms depend on the number of electrons in an atom's outer energy level (atom with a few electrons in its outer energy level tends to lose its electrons and becomes a positively charged ion AND atoms with a nearly full outer energy level tend to gain electrons and become a negatively charged ion

How are electrons pictured in an atom model?

They are pictured in an electric cloud

How many different elements and how many total atoms are in C6H12O6

Three elements, Carbon, Hydrogen, and Oxygen and 24 atoms (6 of Carbon, 12 of hydrogen, 6 of Oxygen)

What do atoms consist of?

Three types of smaller particles: protons, electrons, neutrons

True or False: Ions usually form when electrons are transferred from one atom to another

True

True or False: The formation of an ion results in a full outermost energy level

True

How many different elements and how many total atoms are in NH3?

Two elements, Nitrogen and Hydrogen, and two atoms (one each of Nitrogen and Hydrogen)

How many different elements and how many total atoms are in BO2

Two elements, boron and oxygen and three atoms (1 of boron and 2 of oxygen)

Are charges that attract each other like or unlike?

Unlike

Which of the following is an example of a compound: water, hydrogen gas, oxygen gas or chloride ion?

Water

Name two common compounds in living things?

Water and Oxygen

A sodium atom has one outer electron and a carbon atom has four outer electrons. How might this difference be related to the types of compounds formed by atoms of these two elements?

When sodium loses it's electron it becomes a positively charged ion (called a cation), because it has less electrons then protons. A positivelty charged ion will form strong electrostatic attractions with negatively charged (called anions) ions. This is called ionic bonding. Sodium forms ionic compounds because it loses its electron to achieve a full outer electron shell thus forming a cation that will then form ionic bonding with an anion. Carbon has 4 electrons in its outer shell. To achieve a full outer shell by gaining or losing electrons it would either have to gain 4 electrons or lose 4. (It needs 8 electrons in it's outer shell to have a full shell: The Octet Rule). Gaining or losing electrons takes a lot of energy, and each progressive electron you gain or remove requires a larger amount of energy than the first. The amount of energy required to gain or lose 4 electrons is much too high for it to readily occur. So instead, carbon will share electrons with other atoms forming covalent bonds.

Compare and contrast - How does a molecule differ from an atom?

a molecule is two or more atoms held together by covalent bonds An atom is the smallest basic unit of matter; living things consist of atoms of different elements Dad what else???

What is a molecule?

a molecule si two or more atoms held together by covalent bonds

compound

a substance made of atoms of different elements bonded together in a certain ratio

What do we know about almost all of the substances that make up living organisms?

almost all of the substances that make up living organisms are molecules that are held together by covalent bonds

ion

an atom that has gained or lost one or more electrons

If an atom has a few electrons in its outer energy level what tends to happen?

an atom with ew electrons in its outer energy level tends to lose its electrons

What is an ion?

an ion is an atom that has gained or lost 1 or more electrons

What are all living things based on?

atoms and their interactions

What do living things consist of?

atoms of different elements

what distinguishes one element from another?

atoms of different elements differ in the number of protons they have

covalent bond

atoms share a one of more pairs of electrons

How does a full outermost energy level result?

by the gaining or losing of electrons

What can an element refer to in addition to one particular type of atom?

can refer to a group of atoms of the same type

Scientists no longer believe that atoms....

cannot be broken down into subatomic particles

What do we know about energy levels?

different energy levels can hold different amounts of electrons, the first energy level can hold 2 electrons, the second level can hold 8 electrons

How do different types of atoms differ?

different numbers of electrons and energy levels

ionic bond

forms through the electrical force between oppositely charged ions

What is a trace element?

found in very small amounts in your body but you need them to survive, Ex. iron is needed to transport oxygen in your blood

What types of charges can ions have?

ions can either be positively or negatively charged

Why is an atom electrically neutral?

it has equal number of protons and electrons

what do living things consist of?

living things consist of atoms of different elements and their interactions

How do electrons move around the nucleus?

move in regions called energy levels

Most substances are electrically positive, negative, or neutral?

neutral

What do you know about a compound's properties?

often different from the properties of the elements that make up the compound

element

one particular type of atom, and it cannot be broken down into a simpler substance by ordinary chemical means

What do atoms share?

pairs of electrons in covalent bonds

A glass rod with more protons than electrons has what kind of charge?

positive

Describe protons?

positively charged particle and are found in the nucleus of an atom

One of the kinds of particles found in the nucleus of an atom is?

proton

Describe electrons?

smaller particles that are negatively electric charged and are found outside the nucleus

What happens to electrons in outer energy levels when two atoms form a covalent bond?

the atoms share one or more pairs of electrons

What do you know about atoms of different elements?

they differ in the amount of protons they have

What do you know about atoms of the same element?

they have a specific number of protons that never vary

Describe neutrons?

they have no charge, i.e. they are neutral and are found in the nucleus of an atom

molecule

two or more atoms held together by covalent bonds

When do ions form?

when atoms gain or lose electrons

When are atoms most stable?

when they have a full outermost energy level