Properties of Atoms and the Periodic Table Study Guide

#1 Which two elements do scientists believe are the building blocks of other elements? Hydrogen and Helium

#2 What changes have been made to the model of the atom since Dalton’s simple model. positively charged protons and neutrons centrally located in a nucleus, negatively charged particles in a cloud

#3 Describe and draw the electron cloud model of the atom. Electrons are most likely found in energy levels around the nucleus

#4 Define quarks. Small particles that make up protons and neutrons

#5 Define mass number. How is it determined? the sum of the number of protons and the number of neutrons in the nucleus of an atom; add protons and neutrons

#6 List the characteristics of protons 1+ charge; in the nucleus; mass of 1 AMU; composed of 3 quarks

#7 List the characteristics of electrons 1- charge; in the electron cloud; mass is tiny

#8 List the characteristics of neutrons no charge; in the nucleus; mass of 1 AMU; composed of 3 quarks

#9 What do energy levels hold #9 What do energy levels hold? Is there a maximum number of these particles that each level can hold? Electrons are held in energy levels.Yes. level 1 = 2 electrons max level 2 = 8 electrons max level 3 = 18 electrons max level 4 = 32 electrons max

#10 What are periods? Horizontal rows of elements on the periodic table. -same period, same number of energy levels

#11 What are groups? Vertical columns on the periodic table. -same group, same number of valence electrons and similar chemical and physical properties

#12 Elements in groups 3 through 12 are called the? Transition metals

#13 Define isotopes. Atoms of the same element with different numbers of neutrons.

#14 What does the chemical symbol of an element represent? One capital letter or a capital letter plus one or two smaller letters representing the name of each element.

# 15 What are metalloids? What is another name for a metalloid? Elements with properties of both metals and nonmetals. Semimetals.

#16 What is the periodic table? A table of the elements arranged by increasing atomic number and by changes in physical and chemical properties.

#17 Who organized the first periodic table? How was it organized? Mendeleev arranged the first table by increasing atomic mass

#18 What is the average atomic mass of an element? the weighted-average mass of all isotopes for an element

#19 What are electron dot diagrams? the symbol of an element and dots representing the electrons in the outermost energy level

#20 When is an atom considered to be stable? When its outer level is completed or full of electrons; most elements are stable with 8 valence electrons

#21 Compare the masses of protons, neutrons, and electrons. Protons and neutrons are about the same, 1 AMU. Electrons are much smaller and do not contribute to the mass of the atom.

#22 What is a scaled up model? Models used to visualize things that are too small to see. Ex> model of the atom

#23 What is a scaled down model? Models that allow you to observe something too large to see all at once Ex. Model of the solar system

#24 Draw electron dot diagrams for the following elements: Helium, Bromine, Radium, Francium, Radon, Hydrogen, Lead, and Magnesium

#25 Where in the atom are electrons found? Electrons are found around the nucleus in the electron cloud, in energy levels of increasing energy with increasing distance from the nucleus

#26 How is the identity of an atom determined? By its atomic number, or the number of protons.

#27 What particles are made of quarks? Protons and neutrons

The number of protons in an atom #28 What is atomic number? The number of protons in an atom

#29 Give the period and group number for each of the following elements: Fluorine 2 17 Oxygen 16 Phosphorus 3 15 Nitrogen Sulfur Hydrogen 1

#30 Sodium → Na Metal Barium → Ba metal Calcium → Ca metal What is the chemical symbol for each of the following elements, and classify each as a metal, nonmetal, or metalloid:   Sodium → Na Metal Barium → Ba metal Calcium → Ca metal Lanthanum → La metal Titanium → Ti metal Aluminum → Al metal Arsenic → As metalloid Astatine →At nonmetal Argon → Ar nonmetal

#31 Fill in the following table: Name Mass # Atomic # # of protons # of neutrons Hydrogen-1 1 Hydrogen-2 2 Hydrogen-3 3

#32 Hydrogen-1, Hydrogen-2, and Hydrogen-3 are __________________. isotopes

#33 In a neutral atom, the number of electrons is equal to the number of ______________________. protons

#34 As you move from left to right on the periodic table the number of electrons increases. What happens to the number of electrons as you move down a group? Increases as well