Exam #1 (Ch. 1 and 2)
Round 0.052018 to three significant figures.
0.0520
How many valence electrons are in Na, O and He, respectively?
1, 6, 2
What is the value of the mass number in the isotope 131/53 I?
131
How many electrons are present in an atom of silicon?
14
Given that helium has an isotope , how many electrons does an atom of this helium isotope contain?
2
What is the number 3,000 written in scientific notation using the proper number of significant figures?
3 × 10^3
How many neutrons are present in an atom of the isotope ?
4
How many valence electrons are in an atom of carbon?
4
How many significant figures does the number 5.06305 × 10^4 contain?
6
What is the number 0.0062985632 written in scientific notation to three significant figures?
6.30 × 10^3
What is the number 0.9050 written in scientific notation using the proper number of significant figures?
9.050 × 10^1
Where are the halogens located on the periodic table?
Group VIIA (17)
Where are the alkaline earth metals located on the periodic table?
IIA (2)
Which explains why isotopes have different mass numbers?
Isotopes differ in the number of neutrons each contains.
Tungsten is a metal containing 74 protons, and is used widely in the electronics industry. What is the chemical symbol for tungsten?
W
What statement best describes an intensive property? a.) a property of a substance that does not depend on the quantity of the substance present b.) a property of a substance that depends on the quantity of the substance present c.) a property of a substance that depends on the mass of the substance, but not the volume of the substance d.) a property of a substance that depends on the physical state (solid, liquid, or gas) of the substance e.) a property of a substance that changes based on the mass of the material that is present
a.) a property of a substance that does not depend on the quantity of the substance present
Which statement concerning the classification of matter is FALSE? a.) all matter is either pure substance or a compound b.) an element is a pure substance that cannot be changed into a simpler form of matter by any chemical reaction c.) a compound is a pure substance made up of two or more different elements combined in a definite, reproducible way d.) a pure substance is composed of only one type of component e.) a mixture is the physical combination of two or more pure substances in which each substance retains its own identity
a.) all matter is either pure substance or a compound
Which of the following is an example of physical change? a.) boiling water b.) burning paper c.) a metal losing electrons to become a cation d.) cooking eggs e.) lighting a match
a.) boiling water
The ion K+ is formed by which process? a.) loss of an electron by K b.)gain of proton by K c.)loss of a proton by K d.) gain of an electron by K e.) none of the above
a.) loss of an electron by K
What is the general name given to the elements of Group IA (1)?
alkali metals
When a neutral atom gains one or more electrons, what type of particle is formed?
anion
In a neutral atom, what number equals the number of electrons?
atomic number
Atoms with the biggest radii occur in the _______ region of the periodic table.
bottom left
The ground state electron configuration of chlorine is shown below. Which statement concerning an atom of chlorine is FALSE? Cl 1s2^2s^22p^63s^23p^5 a.) A chlorine atom has 17 total electrons. b.) The outermost energy level in a chlorine atom is n=3. Correct! c.) A chlorine atom has 5 valence electrons. d.) A chlorine atom needs one electron to obtain an octet in its outermost energy level. e.) A chlorine atom has 17 protons.
c.) A chlorine atom has 5 valence electrons
The Aufbau Principle specifies which of the following? a.) Each atomic orbital has a maximum capacity of two electrons. You Answered b.) Two electrons in the same orbital must have opposite spins. c.) Two electrons in the same orbital must be spin paired. d.) Electrons will occupy the lowest energy orbitals that are available. e.) Electrons will half-fill orbitals of equal energy, before any become completely filled.
d.) electrons will occupy the lowest energy orbitals that are available
What kind(s) of particles can be found outside the nucleus of an atom?
electrons
What are the two classes of pure substances?
elements and compounds
What term is used to describe atoms of the same element that have different masses?
isotopes
A student records the measurement 4.8 m. What type of measurement was made?
length
What is the basic unit of volume in the metric system?
liter
What term is used for the elements straddling the "staircase" boundary between the metals and nonmetals?
metalloids
What does the mass number minus the atomic number represent?
number of neutrons
The identity of an atom is determined by what?
number of protons
Conversion of ice to liquid water or liquid water to steam is an example of what kind of change?
physical
How many orbitals are in an s sublevel? How many in a p sublevel?
s: 1, p: 3
What are valence electrons and where are they located?
the outermost electrons in an atom
What is density?
the ratio of the mass of a substance to the volume of the substance
