Sodium (Na) and magnesium (Mg) are both in period 3.
Which element in period 4 is the most chemically active non-metal?
Bromine (Br) is the most chemically active non-metal in period 4.
Which of these is not one of the eight most abundant elements in the Earth's crust?
Mercury (Hg) is not one of the eight most abundant elements in Earth's crust.
What were the names of the two elements the Curies discovered?
Polonium (Po) and radium (Ra) were discovered by the Curies.
What is the last element in period 4?
Krypton (Kr) is the last element in period 4.
Which best describes the sequence of the elements in period 5 of the periodic table?
Period 5 elements progress from alkali metal (Rb) to noble gas (Xe), including transition metals and representative elements.
Which period 3 element will not react naturally?
Argon (Ar), a noble gas in period 3, will not react naturally.
Which alkali metal has fewer than 10 protons in its nucleus?
Lithium (Li), with 3 protons, is an alkali metal with fewer than 10 protons.
What are the first 36 elements of the periodic table?
The first 36 elements are hydrogen (H) through krypton (Kr).
Which period 3 nonmetal is less reactive than sulfur?
Argon (Ar) is a period 3 nonmetal less reactive than sulfur.
What are the first 30 elements of the periodic table?
The first 30 elements are hydrogen (H) through zinc (Zn).
Which lanthanide has the least mass?
Lanthanum (La) is the lanthanide with the least mass.
What is the only metalloid in period 3?
Silicon (Si) is the only metalloid in period 3.
What are the top 8 elements found in the Earth's crust?
Oxygen (O), silicon (Si), aluminum (Al), iron (Fe), calcium (Ca), sodium (Na), potassium (K), and magnesium (Mg) are the top 8 elements in Earth's crust.
Name a main-group element in period 3.
Magnesium (Mg) is a main-group element in period 3.
I am the first element in the fourth period used in making fertilizer. What am I?
Potassium (K) is the first element in period 4 used in making fertilizer.