What defines an element?
A pure substance that cannot be broken down into simpler substances.
What makes up an element, and how many atom types does it contain?
An element is made of atoms and contains only one type of atom.
What physical traits characterize metals?
They are shiny, conduct heat and electricity well, can be shaped, and are almost all solid at room temperature.
How do nonmetals typically conduct heat and electricity?
They are generally poor conductors of heat and electricity.
How do metalloids compare with metals and nonmetals?
They share traits of both, are less brittle than nonmetals, and conduct electricity less well than metals.
By the mid-1800s, what unique building block did scientists associate with each element?
A unique type of atom.
By the mid-1800s, how did scientists model atoms?
As tiny, indivisible balls differing only in mass.
What does an atom’s atomic number count?
The number of protons in its nucleus.
What does an atom’s atomic number identify?
A specific element.
What does an atom’s mass number count?
The total number of protons and neutrons.
How do proton and electron counts compare in a neutral atom?
They are equal.
How do isotopes of the same element differ in their neutron counts?
They have different numbers of neutrons.
What is the proton and electron count relationship between isotopes of one element?
They have the same numbers of protons and electrons.
What does periodic-table atomic mass account for?
All isotopes of an element and their relative abundances.
How is average atomic mass calculated from isotope masses and abundances?
What are the two ways matter can be classified?
As a pure substance or a mixture.
Why are boron and silicon useful in computer chips?
Their semiconducting properties make them useful in computer chips.
Which metal produced the most bubbles with hydrochloric acid?
Magnesium.
What could the indivisible-ball model not fully explain about elements?
Observed patterns in the properties of elements.
Why do scientists use atomic models to visualize atomic structure?
Atoms are too small to observe directly.
What can make constructing a scale model of an atom difficult?
Atoms are too small to observe directly.
What can not-to-scale atomic models show when relative sizes and distances are not the focus?
The numbers, charges, and locations of subatomic particles.
How many protons does an aluminum atom with atomic number 13 have?
13 protons.
How many neutrons does an aluminum atom with mass number 27 have?
14 neutrons.
How many electrons does a neutral aluminum atom with atomic number 13 have?
13 electrons.
What unit do scientists use to measure atomic mass?
Unified atomic mass units (u).
What are the natural abundances of carbon-12 and carbon-13?
Carbon-12 is 98.89% and carbon-13 is 1.11%.
What is the calculated average atomic mass of carbon?
12.0111 u.
What is the average atomic mass of nitrogen using the stated isotope data?
14.008 163 u.
How can you estimate an element’s most common isotope’s mass number from the periodic table?
Round its average atomic mass to the nearest whole number.
What does a flame test use to identify unknown substances?
The properties of elements.
Answer 16 questions on Atomic Structure and Isotopes.
1. A sample is a pure substance that cannot be broken down into simpler substances. What is the sample classified as?
2. A scientist in the mid-1800s describes atoms as tiny, indivisible balls that differ only in mass. Which early view is the scientist expressing?
Go over the full study guide for Atomic Structure and Isotopes.
Read the study guide →Upload your class notes and Revizly writes your flashcards in about a minute.
Flashcard maker