Bio lecture 2 quiz P40-79

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What type of bond results from the sharing of electrons between atoms?

Ionic bond

Hydrogen bond

Covalent bond (correct)

Metallic bond

Which bond occurs between two separate molecules?

Hydrogen bond (correct)

Polar bond

Covalent bond

Ionic bond

What is the effect of electronegativity on covalent bonding?

Atoms with the same electronegativity form polar covalent bonds.

Similar electronegativity leads to formation of ionic bonds.

Higher electronegativity indicates atoms share electrons unequally. (correct)

Electronegativity decreases as you move right on the periodic table.

Which of the following is a characteristic of ionic and covalent bonds?

They exist within a molecule. Signup and view all the answers

Which of the following statements about noble gases is true?

Their electron shells are fully occupied. Signup and view all the answers

What type of covalent bond is formed between two atoms of the same element?

Non-polar covalent bond Signup and view all the answers

What is the most electronegative element?

Fluorine Signup and view all the answers

Why are covalent bonds considered strong?

They require a significant amount of energy to break. Signup and view all the answers

What causes the atomic mass of an element to be rarely an even number?

The presence of a variety of isotopes Signup and view all the answers

What defines a radioisotope?

An isotope that spontaneously emits energy and particles Signup and view all the answers

How does the process of radioactive decay generally occur?

By losing neutrons over time Signup and view all the answers

What is the relationship between an electron's kinetic energy and its position?

Kinetic energy is related to the electron's motion only Signup and view all the answers

Which of the following statements is true regarding electron energy levels?

Electrons are limited to specific allowed energy levels Signup and view all the answers

What is the name of the cloud that contains the electrons closest to the nucleus?

1s orbital Signup and view all the answers

How are electron orbitals organized around the nucleus?

In shells based on energy levels Signup and view all the answers

What follows the 2s orbital in terms of electron orbitals?

2p orbital Signup and view all the answers

What is the primary characteristic of ionic bonds?

They involve the transfer of electrons between atoms. Signup and view all the answers

What happens to the atom that loses an electron during the formation of an ionic bond?

It becomes a positively charged ion. Signup and view all the answers

Which of the following compounds is formed through ionic bonding?

Sodium chloride (NaCl) Signup and view all the answers

What is the shape of p orbitals?

Dumbbell-shaped Signup and view all the answers

What role does electronegativity play in the formation of ionic bonds?

It influences the transfer of electrons between atoms. Signup and view all the answers

How many electrons can the 2p orbitals hold in total?

6 Signup and view all the answers

What is the order of strength among the bonds discussed, from strongest to weakest?

Covalent, Ionic, Hydrogen Signup and view all the answers

How do ionic compounds behave when dissolved in water?

They dissolve easily and conduct electricity. Signup and view all the answers

What is the maximum number of electrons in the first electron shell?

2 Signup and view all the answers

If an atom has 11 protons and 11 electrons, what is its atomic number?

11 Signup and view all the answers

Which molecules can engage in hydrogen bonding?

Molecules with hydrogen attached to an electronegative atom. Signup and view all the answers

How does the strength of a hydrogen bond compare to a covalent bond?

It is significantly weaker than a covalent bond. Signup and view all the answers

How many electrons does the 3s orbital hold?

2 Signup and view all the answers

What is the principle behind an atom's reactivity?

Atoms are inert when their outermost shell is completely full. Signup and view all the answers

In the case of chlorine, if the atomic number is 17, how many neutrons does it have if the mass number is 35.5?

18 Signup and view all the answers

What types of orbitals are present in the second electron shell?

s and p orbitals Signup and view all the answers

What role do multiple hydrogen bonds play in biological structures?

They form stable connections like the DNA double helix and protein structures. Signup and view all the answers

Which statement accurately describes a chemical equation?

It shows reactants on the left side and products on the right side. Signup and view all the answers

What is meant by chemical equilibrium in a reaction?

It refers to a balanced equation where the number of atoms remains constant. Signup and view all the answers

When water is formed as a product of hydrogen and oxygen gas, what is the correct chemical equation?

H2 + O2 → H20 Signup and view all the answers

Which of the following statements about the formation of chemical bonds is true?

Chemical reactions lead to the formation of bonds between two or more elements. Signup and view all the answers

Study Notes

Ions & Isotopes

Atomic mass is typically not an even number due to the presence of isotopes.
Carbon has isotopes C-12 (most abundant), C-13, and C-14, resulting in an average atomic mass of 12.011.
Radioisotopes have unstable nuclei that emit energy and particles to stabilize themselves.
Radioactive decay involves the gradual loss of neutrons from unstable isotopes, turning C-14 into stable C-12.
The decay of isotopes occurs at predictable rates, with half-lives varying from days (P-32) to thousands of years (C-14).

Energy Levels of Electrons

Electrons have energy levels that determine their stability in orbit around the nucleus.
Electrons possess kinetic energy from motion and potential energy based on their distance from the nucleus.
Electrons can only occupy specific orbits corresponding to allowed energy levels and transition between them by gaining or losing energy.

Electron Orbitals

Electrons reside in orbitals or clouds surrounding the nucleus, organized into shells.
The 1s orbital closest to the nucleus holds 2 electrons, followed by the 2s orbital, and then the 2p orbitals (2px, 2py, 2pz) which accommodate a total of 6 electrons.
Higher atomic numbers provide more shells and electrons, with the next levels including 3s and 3p orbitals.

Electron Shells and Orbitals

Most stable electronic configuration for atoms occurs with 8 electrons in the outermost shell (Octet Rule), except for the first shell, which is stable with 2 electrons.
Example: Sodium (Na) has 11 protons and neutrons totaling 12, distributed as follows: 2 electrons in 1s, 2 in 2s, 6 in 2p, and 1 in 3s orbital.

Chemical Bonds

Atoms with full outer electron shells are inert, while those with partially full shells are reactive.
Types of chemical bonds include intramolecular (covalent and ionic) and intermolecular (hydrogen bonds).

Ionic vs Covalent vs Hydrogen Bonds

Ionic and covalent bonds are intramolecular, involving electron exchange or sharing, while hydrogen bonds occur between separate molecules.
Covalent bonds, formed by sharing electrons, are strong and typically occur between atoms with similar electronegativity.
Electronegativity increases across periods and decreases down groups in the periodic table.

Covalent Bonds

Atoms aim to fill their electron shells; noble gases are stable due to full electron shells.
Fluorine is the most electronegative element.
True covalent bonds form between atoms with identical electronegativity, whereas polar covalent bonds occur when atoms differ slightly in electronegativity.

Ionic Bonds

Ionic bonds are electrostatic attractions between oppositely charged ions and are typically stronger than hydrogen bonds.
Commonly formed between metals and non-metals (e.g., sodium and chlorine forming sodium chloride).
Ionic compounds are soluble in water and conduct electricity in solution.

Hydrogen Bonds

Polar molecules exhibit partial charges; in water, oxygen has a partial negative charge, and hydrogens a partial positive charge.
Hydrogen bonds form between molecules like water, ammonia, and alcohols, allowing stability in biological structures.
Multiple hydrogen bonds create stability in DNA structures, protein secondary structures, and enzyme-substrate interactions.

Chemical Reactions

Chemical reactions involve the formation of bonds between atoms producing compounds.
Reactants undergo transformation into products, represented in a chemical equation.
Balanced chemical equations maintain equal counts of each atom on both sides, adhering to the conservation of mass principle.

Upcoming Topic

The next lecture will cover the structure and properties of water.

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Description

This quiz covers the properties of ions, isotopes, and the energy levels of electrons. Students will explore atomic mass variations due to isotopes, understand the concept of radioisotopes, and learn about electron stability in orbitals. Test your knowledge on atomic structure and the behavior of electrons.