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Biology Ch 2 Test
Terms in this set (30)
In the term trace element, the modifier trace means
the element is required in very small amounts
Compared with 31p, the radioactive isotope 32p has
one more neurton
Atoms can be represented by simply listing the number of protons, nuetrons and electrons- f0r example 2p+, 2n0, 2e- for helium. Which one represents the 18O isotope of oxygen
8p+, 10 n0, 8e-
The atomic number of sulfur is 16. Sulfur combines with hydrogen by covalent bonding to form a compound, hydrogen sulfide. Based on the number of valence electrons in a sulfur atom, predict the molecular formula of the compound.
The reactivity of an atom arises from
the existence of unpaired electrons in the valence shell
Which statement is true of all atoms that are anions
the atom has more electron than protons
what coefficients must be placed in the following blanks so that all atoms are accounted for in the product? C6H12O6-> __ C2H6O + __ CO2
Which of the following statements correctly describes any chemical reaction that has reached equilibrium?
The rate of the forward reaction equals the rate of the reverse reaction
Each element is unique and different from other elements because of the number of protons in the nuclei of its atoms. Which of the following indicates the number protons in an atoms. Which of the following indicates the number of protons in an atom's nucleus?
The mass number of an element can be easily approximated by adding together the number of ___ in an atom of that element
protons and neutrons
What is the approximate atomic mass of an atom with 16 neutrons, 15 protons, and 15 electrons
Calcium has an atomic number of 20 and an atomic mass of 40. Therefore, a calcium atom must have
Different atomic forms of an element contain the same number of protons but a different number of neutrons. What are these different atomic form called?
How do isotopes of the same element differ from each other?
number of neutron
The atomic number of carbon is 6. Carbon-14 is heavier than carbon-12 because the atomic nucleus of carbon 14 contains ____ neutrons
Electrons exist only at fixed levels of potential energy. However, if an atom absorbs sufficient energy, a possible result is that
an electron may move to an electron shell farther out from the nucleus
How man electrons does nitrogen have in its valence shell?
Based on electron configuration, which of these elements would exhibit chemical behavior most like that of oxygen?
Fluorine has an atomic number of 9 and a mass number 19. How many electrons are needed to complete the valence shell of fluorine atom?
What is the maximum number of electron in the 1s orbital of an atom?
A covalent chemical bond is one in which
outer-shell electrons of two atoms are shared so as to satisfactory fill the outer electron shells of both atoms
Nitrogen (N) is much more electronegative than hydrogen (H). Which of the following statements is correct about the atoms in ammonia (NH3)?
each hydrogen atom has a partial positive charge
when two atoms are equally electronegative, they will interact to form
nonpolar covalent bonds
what result from an unequal sharing of electrons between atoms
polar covalent bond
what result from the chemical reaction illustrated in
a cation with a net charge of +1, an anion with a net charge of +1
he ionic bond of sodium chloride is formed when
chlorine gains an electron from sodium
the atomic number of chlorine is 17. the atomic number of magnesium is 12. what is the formula for magnesium chloride
which of the following explains most specifically the attraction of water molecules to one another?
A van der Waals interaction is the weak attraction between
the nucleus of one molecule and the electrons of a nearby molecule
Which of the following would be regarded as compounds
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