Which of the following groups contains reactive elements that need to gain only one electron to have a full outer energy level?

alkali metals

alkaline earth metals

halogens

noble gases

In a chemical reaction you cannot create or destroy matter, this statement refers to a. conservation of atoms c. conservation of mass b. conservation of matter d. conservation of motion

How many unpaired electrons are present in the ground state of a phosphorus atom? a. 3 0.0

What did henry moseley determine that contributed to understanding the atom?

How much heat is released when 161 g of steam at 100 degree C cools to ice at 0 degrees celcius

The A-36 steel pipe has a 6061-T6 aluminum core. It is subjected to a tensile force of 200 kN. Determine the average normal stress in the aluminum and the steel due to this loading.

Sodium (NA) and potassium (K) are in the same group in the periodic table. Sodium is in the 11th position. How many valence electrons does potassium have? A) 0 B) 1 C) 9 D) 11

Which of the following is not caused by the moon? a. moonrise b. tides c. eclipses d. sunrise

Approximately how many mineral species have scientists identified? 250 5000 1500 60

A compound is 53.31 % C, 11.18 % H, and 35.51 % O by mass. What is its empirical formula? Insert subscripts as needed.

What is the element Ar classified as in the periodic table?