Evaluate the following statement: concentrations of trace elements in an environment above What is required by generally has no affects on those organisms.Chapter 2.
False. Elevated concentrations of some trace elements such as, cobalt and chromium can be toxic.
Which of the following statements id true about chemical reaction?
They involved the making and breaking of chemical bond.(tips)
this how chemical change occur.
The most common form of calcium has 20 protons 20 neutrons, and 20 electrons. which of the following elements would be an isotope of calcium?
An atom with 20 protons, 21 neutrons, and 20 electrons.
tip: Isotope of an element have the same number of an element of protons, but a different number of neutrons.
cooper an atomic of 29 and a mass number of 64, what would result of an unchanged cooper atom lost two element?
The atomic number would remain 29, and the atom would be cation with a +2 charge.
Tips: the loss or gain of an electrons does not influence the atomic number( number of protons or the mass number ). number of protons plus neutrons os an atom.
A neutral atomic chlorine has an atomic of 17. it has ------- electrons in its third shell.
Radioactive isotopes are useful in scientific research because ...............
They can be used as tracers to follow particular atoms and molecules through metabolic pathways.
Evaluate the following statement: oxygen is not a greenhouse gas, therefore, gases containing oxygen such as ozone, nitrous oxide, and carbon dioxide are not greenhouse gases either.
False. Compounds can have emergent properties that are very different from the elements that form them.
The atomic number od sulfur is 16. sulfur combines with hydrogen by convalent bonding to form a compound hydrogen sulfide. based on the number of valence electrons in sulfur atom, predict the moleculatr formula of the compound.
A PARTICULAR CARBON ISOTOPE HAS AND ATOMIC NUMBER OF 6 AND, AN ATOMIC MASS OF 14. THE RESPECTIVE NUMBER OF NEUTRONS, PROTONS, AND ELECTRONS THAT THIS CARBON ISOTOPE HAS IS_______________
8, 6, and 6.
pharmaceutical researchers are often interested in blocking particular receptor proteins on cell surfaces. what chemical property of a molecule would be must important for this type of application?
THE MOLECULE'S SHAPE.
A NEUTRAL ATOMIC CHLORINE HAS AN ATOMIC OF 17 . IT HAS--------------------ELECTRONS IN ITS THIRD SHELL.
RADIOACTIVE ISOTOPE ARE USEFUL IN SCIENTIFIC REASEARCH BEACAUSE___________?
THEY CAN BE USED US TRACES TO FOLLOW PARTICULAR ATOMS AND MOLECULES THROUGH METABOLIC PATHWAYS.
EVALUATED THE FOLLOWING STATEMEND: OXYGEN IS NOT GREENHOUSE GAS, THEREFORE, GASE CONTAINING OXYGEN, SUCH AS OZONE, NITROUS OXIDE, AND CARBONE DIOXIDE, ARE NOT GREENHOUSE GASE EITHER.
FALSE. COMPOUNDS CAN HAVE EMERGENT PROPERTIES THAT ARE VERY DIFFERENT FROM THE ELEMENTS THAT FORM THEM.
THE CHEMICAL CHARACTERISTICS OR REACTIVITY OF AN ELEMENT DEPEND MOSTLY ON THE_____________
NUMBER OF ELECTRONS IN ITS OUTERMOST SHELL.
WE CAN REPRESENT ATOMS BY LISTING THE NUMBER OF PROTONS, NEUTRON, AND ELECTONS-FOR EXAMPLE. 2P+ 2N0, 2E- FOR HELIUM. WHICH OF THE FOLLOWING REPRESENTS THE 180 ISOTOPE OF OXYGEN?
8P+, 10N0, 8e-
AN UNCHANGED ATOM OF NITROGEN (ATOMIC NUMBER=7) HAS___________?
SEVEN(7) PROTONS AND SEVEN ELECTRONS.
WHAT ARE THE FOUR(4) MOST ABOUNDING ELEMENTS FOUND IN LIVING SYSTEMS?
HYDROGEN, OXYGEN, NITROGEN, AND CARBON.
AN ATOM THAT NORMALLY HAS _______ IN THE OUTER SHELL WOULD NOT TEND TO FORM CHEMICAL BONDS WITH OTHER ATOMS.
EIGHT (8) ELECTRONS
WHICH OF THE FOLLOWING STATEMENTS DESCRIBES A REVERSIBLE REACTION THAT HAS REACH CHEMICAL EQUILIBRUM?
THE RATE OF THE REVERSE REACTION EQUALS THE RATE OF THE FORWARD REACTION. TIPS:THIS IS THE DIFINITION OF CHEMICAL EQUILIBRIUM.
A POLAR COVALENT BOND IS A BOND THAT ________?
HAS SHARED ELECTRONS PULLED CLOSER TO THE MORE ELECTRONEGATIVE ATOM.
POTASSIUM( ATOMIC NUMBER 19 , MASS NUMBER 40) AND SODIUM ( ATOMIC NUIMBER11 NUMBER 23) HAVE SIMILAR CHEMICAL PROPERTIES AND REACTIVE BEHAVIOR. THIS IS BEACUSE UNCHANGE ATOMS OF POTASSIUM AND SODIUM_______________?
HAVE DIFFERENT MASS NUMBER'S AND EACH HAS ONE ELECTRON IN ITS OUTER MOST ELECTRON SHELL.
AN ELEMENT HAS 8 PROTONS , 9 NEUTRONS, AND 8 ELECTRONS, ITS ATOMIC NUMBER AND ATOMIC MASS, RESPECTIVELY ARE_______?
8 AND 17
FOR MOST ATOMS, A STABLE CONTIGURENTION OF ELECTRONS IS ATTAINED WHEN THE ATOM___?
has eight (8) electrons in the outermost shell
which of the following statements correctly discribes any chemical reaction that has reached equilibrium?
the rate of the forward and reverse reactions are equal.
which of the following four(4) statements, its any is true regarding essential element and living organisms?
ALTHOUGH ALL FORM OF LIFE REQUIRE IRON, OTHER ELEMENTS ARE REQUIRED ONLY BY CERTAIN SPECIES.
WHEN ONW OR MORE PAIRS OF VALENCE ELECTRONS ARE SHARED BY TWO NEUTRAL ATOMS, WHAT TYPES OF BONDS IS FORMED?
A COVALENT BOND.
WHAT IS THE ROLE OF VAN DER WAALS INTERATIONS IS BIOLOGICAL MOLECULES?
ALTHOUGH THEY ARE WEAK BONDS, VAN DER WAAS INTERACTIONS HELP TO REINFORCE THE THREE(3) DIMENTIONAL SHAPES OF LARGE MELECULES.
SOME GROUPS OF ELEMENTSS REACT CHEMICALLY IN SIMILAR WAY, FOR EXAMPLE, THE CHEMISTRY OF SODIUM, AND THE CHEMISTRY OF LITHIUM, ARE ALSO SIMILAR.
THESE SIMILARIESTIES IN CHEMISTRY RESULT WHEN DIFFERENT ELEMENTS HAVE SIMILAR__________________________?
NUMBERS OF OUTER-SHELL ELCTRONS.
HYDRONGEN BOND OCCUR WHEN?
PARTIAL OPPOSITE CHARGES ON MOLECULES COME CLOSE ENOUGH TO ATTRACT EACH OTHER.
A COVALENT BOND IS LIKELY TO BE POLAR IF_____
ONE OF THE ATOMS SHARING ELECTRONS IS MUCH MORE ELECTRONEGATIVE
HOW MANY ELECTRONS WOULD B PRESENT IN THE VALENCE SHELL OF SULFUR ATOM( ATOMIC NUMBER 16, MASS MUMBER 32)_______?