Identify the period or group number described for the following case:

a) contains elements C, N and O

b) start with helium

c) Contains the alkali metals

d) end with neon

What is the empirical formula of a substance that consists of 85.60% carbon and 14.40% hydrogen?

If litmus paper is dipped in a very acidic and then in a basic what will happen

A molecule that dissociates in water and gives off hydrogen ions is

Consider the reaction 2Na + Cl2 - 2NaCl. and is Na is Oxidized or reduced

Which reaction will produce a solution that does not conduct electricity? A. CH3OH (l) CH3OH (aq) B. CaBr2 (s) Ca2 + (aq) + 2Br (aq) C. HF (g) + H2O (l) H3O + (aq) + F - (aq) D. NH3 (g) + H2O (l) NH4 + (aq) + OH - (aq)

Americium-241 is used in some smoke detectors. it is an alpha emitter with a half-life of 432 years. how long will it take in years for 45.0 % of an am-241 sample to decay?

What is the purpose of forming a scientific hypothesis? It starts a plan to test your idea It provides the answer to your investigation It allows you to prove your idea is correct

N2 + 3h2 2nh3 how many moles of hydrogen are needed to completely react with two moles of nitrogen?

While in Europe, if you drive 119 km per day, how much money would you spend on gas in one week if gas costs 1.10 euros per liter and your car's gas mileage is 30.0 mi/gal? Assume that 1euro=1.26dollars.

What type of star has an absolute brightness of 1 and a surface temperature around 7,500 °C?