Atoms: The Building Blocks of Matter. Foundations of Atomic Theory. Nearly all chemists in late 1700s accepted the definition of an element as a substance that cannot be broken down further Knew about chemical reactions
Atoms: The Building Blocks of Matter
Each of the salt crystals shown here contains exactly
39.34% sodium and 60.66% chlorine by mass.
2. Write the nuclear symbol for carbon-13.
3. Write the hyphen notation for the element that contains 15 electrons and 15 neutrons.
25% = 0.2575% = 0.75
(2.00g x 0.25) + (3.00g x 0.75) = 2.75g
69.17% Cu-63 – 62.929599 amu
30.83% Cu-65 – 64.927793 amu
(0.6917 x 62.929599) + (0.3083 x 64.927793)
= 63.55 amu
How many grams of helium are there in 2 moles of helium?
2.00 mol He x = ? g He
2.00 mol He x 4.00 g He= 8.00 g He
1 mole He
What is the mass in grams of 3.50 mol of the element copper, Cu?
222 g Cu
What is the mass in grams of 2.25 mol of the element iron, Fe?
126 g Fe
What is the mass in grams of 0.375 mol of the element potassium, K?
14.7 g K
What is the mass in grams of 0.0135 mol of the element sodium, Na?
0.310 g Na
What is the mass in grams of 16.3 mol of the element nickel, Ni?
957 g Ni
A chemist produced 11.9 g of aluminum, Al. How many moles of aluminum were produced?
0.441 mol Al
How many moles of calcium, Ca, are in 5.00 g of calcium?
0.125 mol Ca
How many moles of gold,Au, are in 3.60 × 10−10 g of gold?
1.83 × 10−12 mol Au
How many moles of silver, Ag, are in 3.01 x 1023 atoms of silver?
Given: 3.01 × 1023 atoms of Ag
Unknown: amount of Ag in moles
Ag atoms ×= moles Ag
3.01x1023atomsAg x =0.500 mol Ag
How many moles of lead, Pb, are in 1.50 × 1012 atoms of lead?
2.49 × 10−12 mol Pb
How many moles of tin, Sn, are in 2500 atoms of tin?
4.2 × 10−21 mol Sn
How many atoms of aluminum, Al, are in 2.75 mol of aluminum?
1.66 × 1024 atoms Al
What is the mass in grams of 7.5 × 1015 atoms of nickel, Ni?
7.3 × 10−7 g Ni
How many atoms of sulfur, S, are in 4.00 g of sulfur?
7.51 × 1022 atoms S
What mass of gold,Au, contains the same number of atoms as 9.0 g of aluminum,Al?
66 g Au
Arrangement of Electrons in Atoms
E = hν
Ephoton = hν
Excited neon atoms emit light when falling back to the ground state or to a lower-energy excited state.
The electron configuration of boron is 1s22s22p1. How many electrons are present in an atom of boron? What is the atomic number for boron? Write the orbital notation for boron.
The electron configuration of fluorine is 1s22s22p5. What is the atomic number of fluorine? How many of its p orbitals are filled? How many unpaired electrons does a fluorine atom contain?
[Ne] = 1s22s22p6
Write both the complete electron-configuration notation and the noble-gas notation for iron, Fe.
Write both the complete electron configuration notation and the noble-gas notation for iodine, I. How many inner-shell electrons does an iodine atom contain?
How many electron-containing orbitals are in an atom of iodine? How many of these orbitals are filled? How many unpaired electrons are there in an atom of iodine?
Write the noble-gas notation for tin, Sn. How many unpaired electrons are there in an atom of tin?
Without consulting the periodic table or a table in this chapter, write the complete electron configuration for the element with atomic number 25.
Write both the complete electron-configuration notation and the noble-gas notation for a rubidium atom.
Write both the complete electron configuration notation and the noble-gas notation for a barium atom.