Electrons are found in energy levels around the nucleus as shown in the diagram representing a carbon atom with 6 protons, 6 neutrons and 6 electrons Sub-
Solution: 6 electrons All neutral carbon atoms have 6 protons and 6 electrons d How many neutrons are in the nucleus of a carbon-14 atom
The following three diagrams are carbon atoms: (6 protons, 6 neutrons) (6 protons, How many electrons are found in each of the following: ? in ? in ?
6 oct 2007 · Examples of central atoms: • Carbon has FOUR valence electrons It needs FOUR more electrons to achieve an octet
Carbon • Carbon is in group 4A, so it has four valence electrons and the following electron-dot symbol • We expect carbon atoms to form four covalent
we can predict how many hydrogen atoms will be needed to combine with each of those elements Carbon, with 4 electrons in its valence shell,
Each carbon atom has the same number of protons and electrons, 6 12C has 6 neutrons, 13C has 7 neutrons, and 14C has 8 neutrons and so on
What is the electron configuration for a neutral carbon atom? 2 How many orbitals does carbon contain? 3 How does our angular momentum quantum number, l
In ammonia (NH3), the three hydrogen atoms share one electron each with the nitrogen atom and form three covalent bonds Ammonia has one lone pair All the
Calculate the moles of carbon in 0 0265 g of pencil lead How many aluminum atoms are in a can weighing 16 2 g? 0 0265 g C × 1 mol
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Mole & Molar Mass
Mole (mol): the amount of material counting 6.02214 × 10 23
particles The value of the mole is equal to the number of atoms in exactly 12 grams of pure carbon-12. C-12 = 1 mol C-12 atoms = 6.022 × 10 23
atoms The number of particles in 1 mole is called Avogadro's Number (6.0221421 x 10 23
).
6.022 ×10
23
atoms 1 mol or 1 mol
6.022 ×10
23
atoms
Converting between Number of
Moles and Number of Atoms
Calculate the number of atoms in 2.45
mol of copper. A silver ring contains 1.1 x 10 22
silver atoms. How many moles of silver are in the ring?
2.45 mol Cu ×
6.022 ×10
23
atoms
1 mol
= 1.48 × 10 24
atoms Cu 1.1 ×10 22
atoms Ag × 1 mol
6.022 ×10
23
atoms = 1.8 × 10-2 mol Ag Molar Mass: the mass of 1 mol of atoms of an element An element's molar mass in g/mol is numerically equal to the element's atomic mass in amu.
1 mol C
C or C
1mol C
Converting between Mass and Number of MolesConverting between Mass and Number of Atoms
Calculate the moles of carbon in of
pencil lead. How many aluminum atoms are in a can weighing 16.2 g? C ×
1 mol C
C = 2.21 × 10 -3 mol C Al ×
1 mol Al
26.98 g Al
×
6.022 ×10
23
atoms
1 mol
= 3.62 × 10 23
atoms AlAtoms mol Cu g Al mol Al atoms Al mol Ag Atoms Ag mol C g C
Practice Problems
1. How many atoms are there in each of following?
(a) 3.75 moles of silver (b) 2.36 moles of xenon (c) 158 kg of phosphorus
2. What is the amount, in moles, of each of the following?
(a) of potassium (b) of Ar (c) 2.16 x 10 24
atoms of lead
3. What is the mass of each of the following?
(a) 1.9 x 10 24
atoms of Pb (in g) (b) 4.87 x 10 25
atoms of Zn (in kg) (c) 2.33 x 10 20 atoms of oxygen (in ng)
4. How many molecules are in 2.50 moles of CO
2 ?
5. Calculate the mass , in grams, of 0.433 mol of calcium nitrate.
Hint: Formula Weight of Ca(NO
3 ) 2 = (AW of Ca) + 2(AW of N) + 6 (AW of O)
6. Calculate the number of H atoms in 0.350 mol of C
6 H 12 O 6
References:
Tro, Chemistry: A Molecular Approach 2
nd ed., Pearson Brown/LeMay/Bursten, Chemistry: The Central Science, 12 th ed., Pearson
Answers
1. (a) 2.26 × 10
24
silver atoms; (b) 1.42 × 10 24
xenon atoms (c) 3.07 × 10 27
phosphorus atoms
2. (a) 11.5 moles; (b) 0.295 moles Ar; (c) 3.59 moles
3. (a) ) 6.5 × 10
2 g; (b) 5.29 kg; (c) 6.19 × 10 6 ng
4. 1.51 x 10
24
atoms; 5. 71 Ca(NO 3 ) 2 6. 2.53 x 10 24
H atoms Gram Moles Formulaunits (atoms, molecules, ions) molar mass
Avogadro's
number