Chapter 17 – Properties of Atoms and the Periodic Table

Question Answer
The smallest piece of matter that still retains the properties of the element Atom
Number on the periodic table that represents the number of protons in an atom Atomic Number
Number on the periodic table that is the weighted average mass of the mixture of isotopes that exists naturally for an element Average Atomic Mass
Showed through light spectroscopy that electrons existed in specific energy levels in 1913 Bohr
Father of modern atomic theory – showed with experiments in 1800 that all elements had atoms as their smallest particles Dalton
Ancient Greek who first said all matter was made of small indivisible particles called “atomos” Democritus
Region outside of the nucleus where the electrons are found Electron Cloud
Current atomic model with electrons not as particles in orbits, but wave-particles in areas of probability Electron Cloud Model
Negatively charged particles in an atom Electrons
Vertical column in the periodic table Group or Family
Atoms of the same element that have different numbers of neutrons Isotopes
The sum of the number of protons plus neutrons in the nucleus Mass Number
Put together the first periodic table based on increasing atomic mass Mendeleev
Elements that are found on the left side of the periodic table (left of zigzag dividing line) Metals
Elements that have properties of both metals and nonmetals Metalloids
Changed the periodic table to be in order by atomic number Moseley
Elements found to the right of the zigzag dividing line in the periodic table Nonmetals
Neutral particles in the nucleus of an atom Neutrons
The center of the atom containing protons and neutrons Nucleus
Horizontal row in the periodic table Period
Table of elements arranged according to repeated changes in properties Periodic Table
Positively charged particles in an atom Protons
Smallest known particle that makes up protons and neutrons Quarks
Discovered the positive nucleus at the center of atoms with gold foil experiment in 1911 Rutherford
Discovered electrons with cathode ray tube experiments in 1904 Thompson
Name for elements found in the middle part of the periodic table (families 3-12) Transition elements
Each energy level of an atom can hold a maximum number of what? electrons
The filling order for electrons in a Bohr diagram is 2,8,8,2
What do the dots in a Lewis Electron Dot diagrams represent? electrons in the outer level
What does the chemical symbol represent? the name of an element
The mass number of any element equals what? The protons + the neutrons
To what family do the elements in group 17 belong? halogen family
How are most synthetic elements classed? rare earth metals
What states of matter did we indicate on our periodic tables? Solid, liquid, gas
In what state of matter are most elements at room temperature? solid
Where is the atomic number found? At the top of the element box
What unit is used to measure the size (diameter) of an atom? Angstrom
What do we use to describe or show what something very large or small “looks like?” We use indirect observation to create models
How did Mendeleev arrange the first periodic table? (two things) By increasing mass and similar properties
Why do different metals produce different colors when burned? Electrons are “excited” by added energy, and jump to another energy level. When they “fall back,” they release energy as light. The amount released determines the color seen.
Elements in the same family share similar properties because they have the same number of electrons in the outer energy level.
Elements in Group/Family 1 have what kinds of properties? They are soft metals and react to water (H20)
How do you order elements from smallest to largest? By increasing Atomic mass. (The lower they are on the periodic table, the heavier they are.)
What will the atomic mass of the most common element of any element equal? The atomic mass number (average atomic mass rounded)
How do you indicate a specific isotope of an element? By adding the mass number of that isotope (example: H-1, C-14)
How do we show protons, neutrons and electrons on a Bohr diagram? proton – p+; neutron – n°; electron – e-

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