Properties of an Atom
What are the three main subatomic particles that make up an atom?
Protons, neutrons, and electrons.
What is an isotope?
Isotopes are atoms of the same element that have the same number of protons but different numbers of neutrons.
What does the atomic number of an element represent?
The atomic number represents the number of protons in an atom’s nucleus.
What is the electron configuration for an atom of hydrogen (H)?
1s¹
Which groups of the periodic table primarily contain transition metals?
Transition metals are primarily found in Groups 3 to 12 of the periodic table.
If an atom has an atomic number of 8 and an atomic mass of 16, how many neutrons does it have?
Neutrons = Atomic Mass - Atomic Number = 16 - 8 = 8 neutrons.
Why do isotopes of the same element have different atomic masses?
Isotopes have different numbers of neutrons, which changes their mass but not their chemical properties, as the number of protons (which determines the element) remains the same.
Why does atomic radius decrease across a period from left to right?
As you move across a period, the number of protons increases, which increases the nuclear charge. This stronger attraction pulls the electrons closer to the nucleus, reducing the atomic radius.
What is the noble gas configuration of sodium (Na
)?
[Ne] 3s¹
How do atomic radii trends differ between transition metals and main group elements?
Transition metals show smaller changes in atomic radius across a period compared to main group elements.
What is the atomic symbol for carbon, and what is its atomic number?
The atomic symbol for carbon is C, and its atomic number is 6.
How do you calculate the relative atomic mass of an element if given the abundance and mass of its isotopes?
The relative atomic mass is calculated by multiplying the mass of each isotope by its relative abundance (in decimal form), summing these products, and dividing by the total abundance if necessary (usually 100%).
Why do alkali metals become more reactive as you move down Group 1?
As you move down Group 1, the atomic radius increases, meaning the outer electron is further from the nucleus and less tightly held. This makes it easier for the atom to lose the electron, increasing reactivity.
Draw the Lewis dot structure for carbon
.
C .
.
Which block do the transition metals belong to?
D-Block
An element has an atomic number of 11 and an atomic mass of 23. Write the element’s symbol and explain how many electrons, protons, and neutrons it contains.
The element is Sodium (Na). It has 11 protons (because atomic number = number of protons), 11 electrons (in a neutral atom), and 23 - 11 = 12 neutrons.
An element has three isotopes with the following characteristics:
Isotope A: Mass = 10.012 u, Abundance = 19.91%
Isotope B: Mass = 11.009 u, Abundance = 80.09%
Isotope C: Mass = 12.011 u, Abundance = 0%
Calculate the relative atomic mass of this element.
10.8183
Explain the trend in ionization energy across a period and down a group, and why do noble gases have the highest ionization energies?
Across a period, the stronger nuclear charge holds electrons more tightly. Down a group, electrons are further from the nucleus and easier to remove.
Explain the electron configuration and lewis dot structure and lewis dot structure of sulfur in S
Electron Configuration of Sulfur: 1s² 2s² 2p⁶ 3s² 3p⁴.
Noble Gas Configuration: [Ne] 3s² 3p⁴.
..
: S :
..
Why do transition metals lose 4s2 before 3d?
Transition metals lose electrons from the 4s orbital before the 3d orbital because, upon ionization, the 4s orbital becomes higher in energy than the 3d orbital.