Why do elements in the same group have similar properties

The half life of 226/88 Ra is 1620 years. How much of a 12 g sample of 226/88 Ra will be left after 8 half lives?

Hf is a corrosive gas. at 2.0 atm and 300 k, hf occupies a 4.50 l volume. how many grams of hf are in the volume? 1. 7.3 g 2. 2.74 g 3. not enough information is given. 4. 0.573 g 5. 15.6 g 6. 4.82 g

A shallow river dries up is an example of Condensation Evaporation Precipitation Runoff

Which of the items below could scientists use to date a layer of rock? a raindrop on the rock a fossilized fish a green leaf that fell off of a tree an insect flying near the dig site

Atom tableTomic number mass number number of protons number of neutrons number of electrons symbol

63Ni decays by a first-order process via the emission of a beta particle. The 63Ni isotope has a half-life of 100. years. How long will it take for 65% of the nickel to undergo decay?

Based on the standard free energies of formation, which of the following reactions represent a feasible way to synthesize the product? A. 2C (s) + H2 (g) →C2H2 (g); ΔG∘f=209.2 kJ/molB. N2 (g) + 3H2 (g) →2NH3 (g); ΔG∘f=-33.30 kJ/molC.

How do I find the molar mass of Copper (II) Nitrate?

Describe several main ideas in chemistry

What is the wavelength of a wave having a frequency of 1.75*10^ 14 s^ - 1?