Atomic Number
Mass Number
Atomic Mass
Isotopes
Trends
100
Hydrogen is the most abundant element in the universe. The atomic number of hydrogen is:
What is 1.
100
A phosphorus atom has 15 protons and 16 neutrons. What is the mass number?
What is 31.
100
How do you calculate the atomic mass of an element?
What is add the # of protons with the # of neutrons.
100
What is a good definition for an isotope?
What is each of two or more forms of the same element that contain equal numbers of protons but different numbers of neutrons in their nuclei, and hence differ in relative atomic mass but not in chemical properties.
100
What is the purpose of periodic trends?
Periodic trends, arising from the arrangement of the periodic table, provide chemists with an invaluable tool to quickly predict an element's properties.
200
Another important element is carbon, found in all organic molecules. How many protons are in an atom of carbon?
What is 6
200
What is the mass number of this nucleus?
What is 7.
200
Carbon-12 (12) has an abundance of 98.9% and C-13 (13.003355 amu) has an abundance of 1.1%. What is the average atomic weight of Carbon?
0.989 x 12 = 11.868
0.011 x 13.003355 = 0.143
11.868 + 0.143 = 12.011 amu
Around 12.011 amu (atomic mass units)
200
What makes the isotopes of an element similar?
The same number of protons.
200
What is the periodic trend for atomic radius?
The atomic radius increases down a group. The atomic radius decreases across a period.
300
You need oxygen to breathe. What is the atomic number of oxygen?
What is 8.
300
What is mass number ?
Mass number of an atom is the total number of protons and neutrons present in the nucleus of an atom of an element. It is represented by "A".
300
What is the atomic mass of hydrogen?
What is 1.00.
300
How many neutrons does carbon‐14 have?
What is 8 neutrons.
300
What is the periodic trend for electronegativity?
- Decreases down a group
- Increases across a period.
400
70% of air is nitrogen. Ionized nitrogen produces green and violet aurora colors. Do you know its atomic number?
What is 7.
400
An atom has mass number 23 and atomic number 11. How many protons, electrons and neutrons are present in the atom?
Given - Mass number of atom = 23 Atomic number of atom = 11As, no. of electrons in an atom is equal to an atomic number of the element.So, number of electrons = 11Secondly , number of protons are equal to number of electrons.so, number of protons = 11And number of neutrons = mass number - atomic number = 23−11 = 12so, number of neutrons = 12
So , the atom contains 11 protons, 11 electrons, 12 neutrons.
400
What is the atomic mass of oxygen?
What is 15.99.
400
How do the chemical properties of different isotopes of the same atom compare with one another?
All isotopes of an atom have the same chemical properties. They are identical! They just have different masses.
400
What is the periodic trend for electron affinity?
Electron affinity decreases down a group and increases across a period.
500
Fluorine is the first halogen. Pure fluorine is a corrosive yellow gas. Do you know its atomic number?
What is 9.
500
The difference between the mass number and the atomic number gives the _______.
What is the number of neutrons.
500
What is the atomic mass of lithium?
What is 6.94.
500
What is the difference between K-39 and K-40?
K has 19 protons, so K39 should have 20 neutrons and K-40 should have 21 neutrons. Both have 19 electrons.
500
What is the periodic trend for ionization energy?
IE decreases down a group and increases across a period.