Unit 2 Chemistry: Atoms & Periodic Table

Questions and Answers

How many protons and neutrons are in one atom of?

17 protons, 18 neutrons

Which subatomic particle has the smallest mass?

Nucleus

Electron (correct)

Proton

Neutron

Which group contains the most reactive elements?

Transition Metals

Group 1, Alkali Metals (correct)

Noble Gases

Group 2, Alkaline Earth Metals

Which group of elements will lose 2 electrons?

Group 2, Alkaline Earth Metals Signup and view all the answers

List 4 parts of Dalton's Atomic Theory.

All elements are composed of tiny indivisible particles (atoms), Atoms of the same element are identical, Atoms of different elements can physically mix together or can chemically combine with one another in defined ratios, Chemical reactions occur when atoms are separated, joined, or rearranged. Signup and view all the answers

All elements are composed of tiny indivisible particles.

False Signup and view all the answers

Which element contains 7 protons, 8 neutrons, and 7 electrons?

Nitrogen Signup and view all the answers

Atoms of the same element all contain the same number of?

Protons Signup and view all the answers

Phosphorus has an atomic number of 15 and a mass number of 31. How many protons, neutrons, and electrons does a neutral atom of phosphorus contain?

Protons = 15, Electrons = 15, Neutrons = 16 Signup and view all the answers

Which part of the atom was discovered as a result of the Gold Foil Experiment?

Nucleus Signup and view all the answers

What charge does the nucleus have?

Positive Signup and view all the answers

What surrounds the nucleus?

Electrons Signup and view all the answers

What atomic particle carries a negative charge?

Electrons Signup and view all the answers

What is an isotope?

Atoms of the same element (same # of protons) with different numbers of neutrons Signup and view all the answers

How do you know if a sample of matter contains only iron (Fe) atoms?

All atoms in the sample contain 26 protons. Signup and view all the answers

Where are metals located on the periodic table?

On the left Signup and view all the answers

Where are non-metals located on the periodic table?

On the top right Signup and view all the answers

Where are metalloids located on the periodic table?

Along the stair step line Signup and view all the answers

Metal, non-metal or metalloid? Germanium

Metalloid Signup and view all the answers

Metal, non-metal or metalloid? Magnesium

Metal Signup and view all the answers

Metal, non-metal or metalloid? Bromine

Non-metal Signup and view all the answers

Metal, non-metal or metalloid? Boron

Metalloid Signup and view all the answers

Metal, non-metal or metalloid? Chromium

Metal Signup and view all the answers

Metal, non-metal or metalloid? Nitrogen

Non-metal Signup and view all the answers

What is the charge of the proton?

Positive charge Signup and view all the answers

What is the charge of the neutron?

Neutral/no charge Signup and view all the answers

What is the charge of an electron?

Negative charge Signup and view all the answers

What is the Bohr Model?

Also known as the planetary model; shows an atom in which electrons orbit the nucleus in fixed paths. Signup and view all the answers

How did Mendeleev arrange the first periodic table?

By atomic mass Signup and view all the answers

What did Mendeleev's arrangement of the elements lead scientists to?

Predict the properties of unknown elements Signup and view all the answers

Look at the periodic table for Tellurium (Te) and Iodine (I). How does the arrangement of Tellurium and Iodine contradict the overall principle behind the organization of the periodic table?

Tellurium has a higher atomic mass than Iodine Signup and view all the answers

Magnesium is what type of metal?

Alkaline earth metal Signup and view all the answers

With which group of elements is magnesium most reactive?

Non-metals Signup and view all the answers

What elements are in the Halogen group?

Fluorine, Chlorine, Bromine, Iodine, Astatine Signup and view all the answers

What elements are in the Alkali Metals group?

Hydrogen, Lithium, Sodium, Potassium, Rubidium, Cesium, Francium Signup and view all the answers

Why are the Noble gases considered 'inert' gases?

Undergo fewest chemical reactions, low chemical reactivity Signup and view all the answers

What are the elements in the Noble gases group?

Helium, Neon, Argon, Krypton, Xenon, Radon Signup and view all the answers

Atoms are neutral when there is an equal number of what?

Protons and electrons Signup and view all the answers

Columns of elements in the periodic table are called what?

Groups or families Signup and view all the answers

Groups or families in a periodic table are _____________ similar.

Chemically Signup and view all the answers

Rows in a periodic table are called?

Periods Signup and view all the answers

What is the center of the atom that contains most of the atom's mass?

Nucleus Signup and view all the answers

What is the total number of protons and neutrons in the nucleus of an atom?

Mass number Signup and view all the answers

What is the number of protons in an atom; also the way the elements are numbered today?

Atomic number Signup and view all the answers

What is two or more atoms combined?

Molecule Signup and view all the answers

What is two or more elements combined?

Compound Signup and view all the answers

Study Notes

Subatomic Particles

Protons are positively charged particles found in the nucleus of an atom.
Neutrons are neutral particles that also reside in the nucleus.
Electrons are negatively charged particles that orbit the nucleus.

Atomic Structure

A neutral atom has an equal number of protons and electrons.
Mass number represents the total number of protons and neutrons in the nucleus.
Atomic number indicates the number of protons in an atom and determines the element.

Dalton's Atomic Theory

All elements consist of indivisible particles called atoms.
Atoms of the same element are identical in mass and properties.
Different elements can combine chemically in defined ratios.
Chemical reactions involve the rearrangement, separation, or combination of atoms.

Isotopes

Isotopes are atoms of the same element that have different numbers of neutrons.

The Periodic Table

Elements are organized by atomic number in rows (periods) and columns (groups or families).
Group 1 contains the most reactive elements, known as Alkali Metals.
Group 2 contains Alkaline Earth Metals which typically lose 2 electrons.

Reactivity and Element Classification

Metals are located on the left side of the periodic table, while nonmetals occupy the top right.
Metalloids are found along the stair-step line, embodying properties of both metals and non-metals.

Chemical Properties of Elements

Noble gases are categorized as inert gases because of their low reactivity.
The Halogen group includes highly reactive elements such as Fluorine and Chlorine.

Key Experiments and Models

The Gold Foil Experiment led to the discovery of the nucleus, which is positively charged.
The Bohr Model illustrates that electrons orbit the nucleus in fixed paths, resembling a planetary system.

Specific Elements

Nitrogen has 7 protons, 8 neutrons, and 7 electrons.
Phosphorus has an atomic number of 15, consisting of 15 protons, 15 electrons, and 16 neutrons.

Molecular and Compound Definition

A molecule is formed when two or more atoms bond together.
A compound is created when two or more different elements chemically combine.

Summary of Charges

Protons carry a positive charge; neutrons are neutral; electrons have a negative charge.

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Description

Test your knowledge of atoms and the periodic table with this quiz based on Unit 2 of your chemistry curriculum. Explore key concepts like protons, neutrons, and the reactivity of different groups of elements. Perfect for mastering essential chemistry terms!