Please help, and if you could also give me a step by step that would be awesome!!

4.4 g

Explanation:

Step 1: Write the balanced equation

Cu + 4 HNO₃ ⇒ Cu(NO₃)₂ + 2 NO₂ + 2 H₂O

Step 2: Calculate the moles corresponding to 3.2 L of NO₂ at STP

At standard temperature and pressure, 1 mole of NO₂ occupies 22.4 L.

3.2 L × 1 mol/22.4 L = 0.14 mol

Step 3: Calculate the moles of Cu needed to produce 0.14 moles of NO₂

The molar ratio of Cu to NO₂ is 1:2. The moles of Cu needed are 1/2 × 0.14 mol = 0.070 mol.

Step 4: Calculate the mass corresponding to 0.070 moles of Cu

The molar mass of Cu is 63.55 g/mol.

0.070 mol × 63.55 g/mol = 4.4 g

alkaline metals are lithium, sodium, rubidium, potassium, cesium and francium.

alkali metals have electronegativity from 0.7 to 1, lowest in periodic table of elements, which means that alkali metals (i group in periodic table) has positive oxidation number in compounds.

electronegativity is a chemical property that describes the tendency of an atom to attract a shared pair of electrons towards itself.

alkaline metals (far left in main group) have lowest ionizations energy and easy remove valence electrons,

for example, potassium is the alkali metal and has a single valence electron in the outer electron shell.

electron configuration of potassium is: ₁₉k 1s²2s²2p⁶3s²3p⁶4s¹.

they can not exist alone in nature, because they are very reactive.