The molar mass of two equally sized samples of unknown gaseous compounds is shown in the table. Molar Mass Comparison Gas Molar Mass A 17 g/mol B 36.5 g/mol Which statement describes the density and diffusion of both gases at STP? Gas A has a higher density and diffuses faster than Gas B. Gas A has a higher density and diffuses slower than Gas B. Gas A has a lower density and diffuses faster than Gas B Gas A has a lower density and diffuses slower than Gas B.

Effusion  is the process of a gas being poured out through a hole diametrically smaller than the structural exit of the container.

A lighter gas effuses faster than a heavier gas.

Thus gas A has a lower density and effuses slower than Gas B.

Explanation:

assuming that your periodic table has eighteen columns, you should highlight   the four elements in the third column from the left of the table.

neutral atoms of elements after calcium contain d electrons. the energy of d orbitals of a particular main shell lies between the energy of the s and p orbitals of the next main shell. for example, electrons in the have energy higher than those in the orbital while lower than those of the orbital.

by the aufbau principle, electrons fill orbitals one at a time, starting from those of the lowest energy. the orbital is therefore filled right after orbitals and before orbitals.  

potassium has electron configuration and calcium . the s orbital of a main shell holds a maximum of two electrons. the next element would thus have the electron configuration and satisfy the requirements.

a neutral atom of the element contains three electrons on top of the most recent noble gas element. it should thus be placed in the third column of the periodic table. both scandium and yttrium would satisfy the conditions. an aufbau diagram indicates that the 4f orbital is filled before the 5d. however, it appears that exceptions exists for both lanthanum and actinium. neutral atoms of the two d-block elements also demonstrate the and should be highlighted as well.

gold is my favorite solid.